meine Einträge sind schon richtig.
nur, ist wohl ein spezielles Problem von web und gmx.:
550 Invalid DNS MX or A/AAAA resource record
Problem:
The sender domain of the email server you are using is not configured in
the domain name service (DNS) in accordance with RFC.
Solution:
Check the following DNS problems and correct them if necessary:
Neither an A nor an MX record is configured in the DNS for the
sender domain.
The MX record points to a domain name that cannot be resolved.
The MX record refers directly to an IP address.
The MX server does not have a valid A record but only a CNAME record
For more information about your DNS configuration, for example, contact
http://www.intodns.com.
Gruß, Ulrich