Mail gone after restore

Hey,

I moved about 10 domains yesterday evening from my old server to the new one.
I did this by making a full backup and restoring that backup on the new server.

After doing that, the mail did not appear to be restored. The users and aliases were restored.

Is it possible to backup the old mail from the old server, move it to the new server and add it to the already received new mail?

Thanks

You might be experiencing this bug: https://www.virtualmin.com/node/32380 (solution is there too)