Issue Incoming email issue from Twitter and Instagram

[Ekushey]

Server operating system version

AlmaLinux 9.5

Plesk version and microupdate number

Plesk Obsidian v18.0.67

Facing an weird issue, emails from Twitter and Instagram aren't arriving, though emails from everywhere else are coming fine. There are multiple domains / accounts on the server, they are all having the same issue. Didn't find anything related on /var/log/maillog, unsure why this might be happening. Any clues anyone?

 

[Sebahat.hadzhi]

When you say there is nothing related in the maillog do you mean there are no entries for the supposed messages whatsoever? Do you have any greylists configured for the mailboxes in question?