{"id":18945413,"date":"2026-06-22T19:08:35","date_gmt":"2026-06-22T19:08:35","guid":{"rendered":"https:\/\/wordpress.org\/support\/?post_type=topic&#038;p=18945413"},"modified":"2026-06-22T19:57:47","modified_gmt":"2026-06-22T19:57:47","slug":"constant-authentication-failed-errors","status":"publish","type":"topic","link":"https:\/\/wordpress.org\/support\/topic\/constant-authentication-failed-errors\/","title":{"rendered":"Constant &#8220;Authentication Failed&#8221; Errors"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\">I use Post SMTP on many sites, and I also install the pro version once the free plugin is operational. I am using version 3.9.4 of Post SMTP. Unfortunately, I have not been able to successfully send an email from one site.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">During the setup process, I used the same exact server settings I always use on other sites. I use a password manager, and I copied the username (email address) from there, as well as the password, to help avoid typos. Nothing succeeded.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">I am able to log into the webmail for this email account using the same exact credentials. I also deleted the email account in question from my email client, and recreated the email account using the same copied-and-pasted credentials. No problems.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Can you think of anything I might have missed? I am going to raise a ticket with my email provider to see if perhaps the server&#8217;s IP address might be blocked for some reason, but I cannot think of anything else that could cause this.<\/p>\n","protected":false},"template":"","class_list":["post-18945413","topic","type-topic","status-publish","hentry"],"jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/wordpress.org\/support\/wp-json\/wp\/v2\/topic\/18945413","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/wordpress.org\/support\/wp-json\/wp\/v2\/topic"}],"about":[{"href":"https:\/\/wordpress.org\/support\/wp-json\/wp\/v2\/types\/topic"}],"version-history":[{"count":1,"href":"https:\/\/wordpress.org\/support\/wp-json\/wp\/v2\/topic\/18945413\/revisions"}],"predecessor-version":[{"id":18945448,"href":"https:\/\/wordpress.org\/support\/wp-json\/wp\/v2\/topic\/18945413\/revisions\/18945448"}],"wp:attachment":[{"href":"https:\/\/wordpress.org\/support\/wp-json\/wp\/v2\/media?parent=18945413"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}