Same problem
We have 10 licenses in domain network.
The avast service opens a lot of connection to different external IPs port 53 tcp on 4 out of 10 PC's
There are so much open connections that there is port exhaustion, no free ports available for other services, so SMB isn't working anymore, browsing is not working.
Disabling the avast service solves the problem...
Can't find the solution