Q: Customer is sometimes getting duplicate email, but there is no forwarding setup that could cause a loop.
A: How do they read their email?
Maybe they have local AV scanners timing out connections and/or taking too
long to scan their incoming email causing duplicates?
It happens. The fix for that it is to increase the mail server timeout from 1 to something like 5 minutes in their mail program.
If you don't see the duplicates in their webmail it's usually not a service
issue that needs to be fixed server side with their account.
A: How do they read their email?
Maybe they have local AV scanners timing out connections and/or taking too
long to scan their incoming email causing duplicates?
It happens. The fix for that it is to increase the mail server timeout from 1 to something like 5 minutes in their mail program.
If you don't see the duplicates in their webmail it's usually not a service
issue that needs to be fixed server side with their account.