Looking for logging into the Auth 503 Auth Command Used When Not Advertised site and are not getting the correct working link for it? In such a case, you can use the links given here by searching your desired login page in the search box. If the page is present on our website then you will get all the links related to the Auth 503 Auth Command Used When Not Advertised site. After that you can login as usual with your login credentials.
https://serverfault.com/questions/313562/exim-configuration-503-auth-command-used-when-not-advertised
https://github.com/PHPMailer/PHPMailer/issues/1447
https://github.com/nodemailer/nodemailer/issues/18
https://forum.ubuntuusers.de/topic/postfix-503-auth-command-used-when-not-adverti/
https://de.comm.provider.mail.narkive.com/ZJxPntQf/mailversand-klappt-nicht-warum
https://community.sophos.com/products/unified-threat-management/f/mail-protection-smtp-pop3-antispam-and-antivirus/49385/utm9-transparent-smtp-proxy-03-auth-command-used-when-not-advertised
https://www.aqua-mail.com/forum/index.php%3Ftopic%3D3933.0
https://lists.gt.net/exim/users/37585
https://www.linuxquestions.org/questions/linux-software-2/smtp-error-503-auth-command-used-when-not-advertised-4175446555/
https://lists.exim.org/lurker/message/20040902.003002.43123677.de.html
https://sourceforge.net/p/assp/tickets/37/
https://www.php-resource.de/forum/showthread/t-83940.html
https://forums.cpanel.net/threads/configuration-for-sending-emails.614619/