Marco van Oostende - 2020-02-12 09:40:23
Hi Konstantin,
I've been playing with the PHP verifyEmail class. Worked quite nice until I started using it for a large website with lots of validations. It seems there are now websites that do not accept this kind of validation anymore, where the 'rcpt to:' command throws a 550 5.5.1 Protocol error. The requested user is actually valid for that mail server.
This can be tested with the following:
telnet mx.transip.email 25
Trying 86.105.244.9...
Connected to mx.transip.email.
Escape character is '^]'.
220-mx.transip.email ESMTP
helo hi
250 mx5.mail.transip.nl
mail from: <validuser@gmail.com>
250 2.1.0 Ok
rcpt to: <info@zuydfiets.nl>
550 5.5.1 Protocol error
Did you encounter this behaviour before, is there already a fix for it? Main issue is that 550 is of course that 550 is the same error message as unknown user besides the 5.5.1 vs 5.1.1 subcode.