You don't have a valid hostname set and cannot add valid A record

i try to change hostname in order to be able to send mails and i found this error


i goto edit zone records for that domain and try to add A record

server     86400     IN     A     mydomain.com.

it gives me error says bad dotted quad

i remove the ending dot to be like this

server     86400     IN     A     mydomain.com.

still the same error which says bad dotted quad

i put instead of my domain the ip address it solves the bad dotted quad BUT
still the change hostname page shows the same error on the above image !!

what to do to set my hostname and make postfix send mails

thanks in advance.

after updating the A record you need to wait probably