I have a varius domains registered on fastcomet, and I setup gmail (free, no g-suite), to send and receive the mails. I have the same configurations for all my domain, and different hosting provider, but only for one, specific domain, almost all mail (sent or received) as marked as spam.
My actual configuration is:
MX mydomainDOTcom server de4.fcomet.com priority 10
TXT mydomainDOTcom “v=spf1 a:5817.submission.antispamcloudDOTcom a:release.antispamcloudDOTcom -all”
Fastcomet support says all is OK, but the problem remains,
what is wrong?