{"id":13416,"date":"2026-09-07T08:48:33","date_gmt":"2026-09-07T06:48:33","guid":{"rendered":"https:\/\/mybox.com\/help\/?post_type=manual_kb&#038;p=13416"},"modified":"2026-09-07T08:48:37","modified_gmt":"2026-09-07T06:48:37","slug":"mail-app-connection-errors-faq-what-cannot-connect-to-server-password-incorrect-and-connection-timed-out-mean","status":"publish","type":"manual_kb","link":"https:\/\/mybox.com\/help\/en\/knowledgebase\/mail-app-connection-errors-faq-what-cannot-connect-to-server-password-incorrect-and-connection-timed-out-mean\/","title":{"rendered":"Mail app connection errors FAQ: what \u201cCannot Connect to Server,\u201d \u201cPassword Incorrect,\u201d and \u201cConnection Timed Out\u201d mean"},"content":{"rendered":"\n<div class=\"translation-block translation-block-merged\">\n<p class=\"wp-block-paragraph\">Mail app connection errors such as \u201cCannot Connect to Server,\u201d \u201cPassword Incorrect,\u201d and \u201cConnection Timed Out\u201d are general messages, not complete SMTP status codes. They usually point to one of three areas: the app cannot reach the outgoing SMTP server, the app is not authenticated with that server, or the connection is taking too long and is being blocked or interrupted.<\/p>\n\n\n\n<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_86 ez-toc-wrap-left counter-hierarchy ez-toc-counter ez-toc-custom ez-toc-container-direction\">\n<div class=\"ez-toc-title-container\">\n<p class=\"ez-toc-title\" style=\"cursor:inherit\">Table of Contents<\/p>\n<span class=\"ez-toc-title-toggle\"><\/span><\/div>\n<nav><ul class='ez-toc-list ez-toc-list-level-1 ' ><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/mybox.com\/help\/en\/knowledgebase\/mail-app-connection-errors-faq-what-cannot-connect-to-server-password-incorrect-and-connection-timed-out-mean\/#What_does_%E2%80%9CCannot_Connect_to_Server%E2%80%9D_mean\" >What does \u201cCannot Connect to Server\u201d mean?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/mybox.com\/help\/en\/knowledgebase\/mail-app-connection-errors-faq-what-cannot-connect-to-server-password-incorrect-and-connection-timed-out-mean\/#What_does_%E2%80%9CConnection_Timed_Out%E2%80%9D_mean\" >What does \u201cConnection Timed Out\u201d mean?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/mybox.com\/help\/en\/knowledgebase\/mail-app-connection-errors-faq-what-cannot-connect-to-server-password-incorrect-and-connection-timed-out-mean\/#What_does_%E2%80%9CPassword_Incorrect%E2%80%9D_mean\" >What does \u201cPassword Incorrect\u201d mean?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-4\" href=\"https:\/\/mybox.com\/help\/en\/knowledgebase\/mail-app-connection-errors-faq-what-cannot-connect-to-server-password-incorrect-and-connection-timed-out-mean\/#Does_the_error_affect_sending_receiving_or_both\" >Does the error affect sending, receiving, or both?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-5\" href=\"https:\/\/mybox.com\/help\/en\/knowledgebase\/mail-app-connection-errors-faq-what-cannot-connect-to-server-password-incorrect-and-connection-timed-out-mean\/#Are_these_messages_SMTP_IMAP_or_POP3_error_codes\" >Are these messages SMTP, IMAP, or POP3 error codes?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-6\" href=\"https:\/\/mybox.com\/help\/en\/knowledgebase\/mail-app-connection-errors-faq-what-cannot-connect-to-server-password-incorrect-and-connection-timed-out-mean\/#What_does_a_certificate_warning_mean\" >What does a certificate warning mean?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-7\" href=\"https:\/\/mybox.com\/help\/en\/knowledgebase\/mail-app-connection-errors-faq-what-cannot-connect-to-server-password-incorrect-and-connection-timed-out-mean\/#What_does_offline_mode_mean\" >What does offline mode mean?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-8\" href=\"https:\/\/mybox.com\/help\/en\/knowledgebase\/mail-app-connection-errors-faq-what-cannot-connect-to-server-password-incorrect-and-connection-timed-out-mean\/#How_to_identify_the_correct_check\" >How to identify the correct check<\/a><\/li><\/ul><\/nav><\/div>\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"What_does_%E2%80%9CCannot_Connect_to_Server%E2%80%9D_mean\"><\/span>What does \u201cCannot Connect to Server\u201d mean?<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">This message means the mail app could not establish a connection with the mail server it was trying to use. For sending, the relevant server is the outgoing SMTP server. Outlook and other mail clients can show this type of message when the connection to the SMTP server fails.<\/p>\n\n\n\n<\/div>\n\n<div id=\"mybox-1809580297\" class=\"mybox-content mybox-entity-placement\"><div class=\"early-access-banner-inpost\">\r\n  <div class=\"banner-left-inpost\">\r\n    <div class=\"icon-box-inpost\">\r\n      <img decoding=\"async\" src=\"https:\/\/mybox.com\/help\/wp-content\/uploads\/2026\/02\/square-info-icon.svg\" alt=\"Info\">\r\n    <\/div>\r\n    <div class=\"text-box-inpost\">\r\n      <span class=\"label-inpost\"><span class=\"translation-block translation-block-banner-text\">Early access<\/span><\/span>\r\n      <h4><span class=\"translation-block translation-block-banner-text\">Still need help?<\/span><\/h4>\r\n      <p><span class=\"translation-block translation-block-banner-text\">Contact our customer service team.<\/span><\/p>\r\n    <\/div>\r\n  <\/div>\r\n\r\n  <div class=\"banner-right-inpost\">\r\n    <a href=\"https:\/\/panel.mybox.com\/helpdesk2\/v\/list\/\" class=\"banner-button-inpost\"><span class=\"translation-block translation-block-banner-text\">Message us<\/span><\/a>\r\n  <\/div>\r\n<\/div><\/div>\n\n<div class=\"translation-block translation-block-merged\"><p class=\"wp-block-paragraph\">The error may be caused by a connection that is blocked or by a connection that cannot be completed. Errors 0x8004210B and 0x80042109 are examples of Outlook errors linked to a failed connection with the outgoing SMTP server. The connection may time out or be blocked. <a href=\"https:\/\/mybox.com\/help\/knowledgebase\/troubleshooting-outlook-errors-0x8004210b-and-0x80042109\/\">Read more about Outlook SMTP connection errors<\/a>.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"What_does_%E2%80%9CConnection_Timed_Out%E2%80%9D_mean\"><\/span>What does \u201cConnection Timed Out\u201d mean?<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">A timeout means the mail app started trying to connect, but the connection was not completed within the expected time. For the outgoing mail path, this usually points to a connection problem between the app and the SMTP server. The connection may be blocked, or the server may not be reachable from the app at that time.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">A timeout is different from a rejected password. With a timeout, the app has not completed the server connection. With an authentication error, the server connection is available but the app has not successfully logged in.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"What_does_%E2%80%9CPassword_Incorrect%E2%80%9D_mean\"><\/span>What does \u201cPassword Incorrect\u201d mean?<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">In a mail app, \u201cPassword Incorrect\u201d can mean that the app is not properly authenticated to the outgoing SMTP server. The same type of problem may appear as \u201cSender address rejected: not logged in.\u201d This happens when the app tries to send a message without correctly logging in to the outgoing mail server. <a href=\"https:\/\/mybox.com\/help\/knowledgebase\/sender-address-rejected-not-logged-in\/\">See the explanation of the \u201cnot logged in\u201d SMTP error<\/a>.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Check the account credentials saved in the mail app and confirm that the app is using the account details required by the outgoing server. Re-entering a password can help when the saved password is no longer accepted, but the message can also indicate that SMTP authentication has not been completed correctly.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"Does_the_error_affect_sending_receiving_or_both\"><\/span>Does the error affect sending, receiving, or both?<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<figure class=\"wp-block-table\"><table><thead><tr><th>Error area<\/th><th>What it usually identifies<\/th><th>Mail function affected<\/th><\/tr><\/thead><tbody><tr><td>Outgoing SMTP connection<\/td><td>The app cannot establish a connection with the outgoing server<\/td><td>Sending<\/td><\/tr><tr><td>SMTP authentication<\/td><td>The app is not properly logged in to the outgoing server<\/td><td>Sending<\/td><\/tr><tr><td>Incoming mail connection<\/td><td>A separate incoming mail connection problem<\/td><td>Receiving<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">The SMTP errors described in the mybox Help Center concern the outgoing mail server, so they identify a sending problem. They do not, by themselves, show that incoming mail is also affected. A mail app can have a working incoming connection while its outgoing SMTP connection is failing.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"Are_these_messages_SMTP_IMAP_or_POP3_error_codes\"><\/span>Are these messages SMTP, IMAP, or POP3 error codes?<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Not usually. \u201cCannot Connect to Server,\u201d \u201cPassword Incorrect,\u201d and \u201cConnection Timed Out\u201d are user-facing descriptions shown by the mail app. A sending mail server normally returns a three-digit SMTP error code when delivery fails. Those codes provide a more specific indication of the reason for the failure. <a href=\"https:\/\/mybox.com\/help\/knowledgebase\/smtp-error-codes-and-a-list-of-codes-with-explanations\/\">Learn how SMTP error codes identify delivery problems<\/a>.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The wording alone does not identify whether the failed connection is for incoming mail or outgoing mail. Check which action failed. If the message appeared while sending, focus on the outgoing SMTP connection and authentication. If it appeared while checking for new messages, focus on the incoming mail connection.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"What_does_a_certificate_warning_mean\"><\/span>What does a certificate warning mean?<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">A certificate warning is a separate security warning from the connection and authentication messages described above. It should not be treated as proof that a password is wrong or that the SMTP server has rejected the message. Record the exact warning and the mail action that triggered it before changing account settings.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"What_does_offline_mode_mean\"><\/span>What does offline mode mean?<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Offline mode means the mail app is not attempting its normal server connection at that moment. A message shown while the app is offline is not the same as an SMTP authentication rejection. Return the app to its normal connected state, then check whether the problem occurs while sending or while receiving.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"How_to_identify_the_correct_check\"><\/span>How to identify the correct check<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<ol class=\"wp-block-list\">\n<li>Note whether the message appeared while sending or receiving.<\/li>\n\n\n\n<li>For a sending failure, check the outgoing SMTP connection first.<\/li>\n\n\n\n<li>For \u201cPassword Incorrect\u201d or \u201cnot logged in,\u201d check the account authentication used for the outgoing server.<\/li>\n\n\n\n<li>For \u201cConnection Timed Out,\u201d check the connection path to the server because the session was not completed.<\/li>\n\n\n\n<li>If the app shows a three-digit SMTP code, use that code as the more specific description of the sending failure.<\/li>\n<\/ol>\n<\/div>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"template":"","format":"standard","manualknowledgebasecat":[41],"manual_kb_tag":[],"class_list":["post-13416","manual_kb","type-manual_kb","status-publish","format-standard","hentry","manualknowledgebasecat-email"],"_links":{"self":[{"href":"https:\/\/mybox.com\/help\/en\/wp-json\/wp\/v2\/manual_kb\/13416","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/mybox.com\/help\/en\/wp-json\/wp\/v2\/manual_kb"}],"about":[{"href":"https:\/\/mybox.com\/help\/en\/wp-json\/wp\/v2\/types\/manual_kb"}],"author":[{"embeddable":true,"href":"https:\/\/mybox.com\/help\/en\/wp-json\/wp\/v2\/users\/1"}],"version-history":[{"count":1,"href":"https:\/\/mybox.com\/help\/en\/wp-json\/wp\/v2\/manual_kb\/13416\/revisions"}],"predecessor-version":[{"id":13417,"href":"https:\/\/mybox.com\/help\/en\/wp-json\/wp\/v2\/manual_kb\/13416\/revisions\/13417"}],"wp:attachment":[{"href":"https:\/\/mybox.com\/help\/en\/wp-json\/wp\/v2\/media?parent=13416"}],"wp:term":[{"taxonomy":"manualknowledgebasecat","embeddable":true,"href":"https:\/\/mybox.com\/help\/en\/wp-json\/wp\/v2\/manualknowledgebasecat?post=13416"},{"taxonomy":"manual_kb_tag","embeddable":true,"href":"https:\/\/mybox.com\/help\/en\/wp-json\/wp\/v2\/manual_kb_tag?post=13416"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}