> We are mailing from our own CRM system but using Ionos (1and1.com) as our 
> mail service.

You're setting yourselves up to fail by mailing out of a server shared
by thousands of other customers. The error messages you quote testify
to that. Don't do it.

-- 
Atro Tossavainen, Chairman of the Board
Infinite Mho Oy, Helsinki, Finland
tel. +358-44-5000 600, http://www.infinitemho.fi/
_______________________________________________
mailop mailing list
[email protected]
https://list.mailop.org/listinfo/mailop

Reply via email to