Hello,
We have custom domains. Both new and not registered before. No history yet.
Both DNS records are managed by Microsoft 365 Online and set automatically. Emails are hosted by Microsoft Online Cloud.
Both DKIM, SPF, DMARC records are valid.
One of our custom domains is not having problems with getting and sending emails.
But one of them is having a problem with sending emails to
giant companies using Symantec Gateway.
Not delivering to the receiver and not put into the spam folder. (Verdict as spam and action: deleted)
We provided to get added to the whitelist and at this period our emails delivered without any problem. We also have sent the headers to Microsoft. They said there is no reason to mark it as spam. Everything is fine.
We have no chance to add our domain to the whitelists of these companies.
What should we do?