PHP Classes

Doesn't always work

Recommend this page to a friend!

      Verify e-mail  >  All threads  >  Doesn't always work  >  (Un) Subscribe thread alerts  
Subject:Doesn't always work
Summary:Some addresses give a 550 Protocol Error though exists
Author:Marco van Oostende
Date:2020-02-12 09:40:23

  1. Doesn't always work   Reply   Report abuse  
Picture of Marco van Oostende 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 25
Connected to
Escape character is '^]'. ESMTP
helo hi
mail from: <>
250 2.1.0 Ok
rcpt to: <>
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.

  2. Re: Doesn't always work   Reply   Report abuse  
Picture of Konstantin Granin Konstantin Granin - 2023-02-10 14:11:56 - In reply to message 1 from Marco van Oostende