Registration mail blocked by

Hello there, I had some trouble creating an account here because the pio mail server is blacklisted:

Maybe someone cares about that.


We don’t have a mail server. We use Sendgrid service.

Thanks for your reply.
Looks like Sendgrid has problems with sending/relaying SPAM and you are affected because your mails through (some of their servers?) are black listed. I just wanted to let you know.

Best not listed in

Should their server be listed or not?

Obviously their server has been removed in the meantime.
Here is my mail server log quote:

Sep 29 15:36:00 www postfix/smtpd[8676]: NOQUEUE: reject: RCPT from[]: 554 5.7.1 Service unavailable; Client host [] blocked using; Blocked - see;