I recently migrated from one server where my mail settings worked without a problem to a new server which now results in the following error:
Server responded: 503 AUTH command used when not advertisedrn.
The full SMTP log is:
19:16:12 [MailBee SMTP v. 18.104.22.168. Registered version] 19:16:12 [Connecting to server mail.example.co.uk at port 25 using default domain] 19:16:12 [Domain specified in FromAddr, example.co.uk used] 19:16:12 [Entering ESMTP authentication mode] 19:16:12 [Sending ehlo] 19:16:12 [Using PLAIN ESMTP authentication] 19:16:12 [Error: Negative or void server response] 19:16:12 [Server responded: 503 AUTH command used when not advertisedrn] 19:16:12 [Possible error reason: PLAIN authentication type (auth plain command) is not supported by this server] 19:16:12 [Error: Connection failure] 19:16:12 [Error: Not connected]
Please could someone point me in the right direction as to why this is failing.