Hi I have exactly the same problem, the txt field is ok but for the two CNAME fields my hosting provider forces a dot at the end.
I get an ‘invalid’ message for my two CNAME fields :
mailpoet1._domainkey.frenchpoetry.fr dkim1.sendingservice.net
and
mailpoet2._domainkey.frenchpoetry.fr dkim2.sendingservice.net
