Is DMARC included in your 'etc'? I think thats needed for gmail these days. If rdns, dkim, spf and dmarc are there, try checking your IPs reputation (senderscor

Is DMARC included in your 'etc'? I think thats needed for gmail these days. If rdns, dkim, spf and dmarc are there, try checking your IPs reputation (senderscore) that could be it.