Slow events after switching the network/router

Hi Experts,
I have 1 asterisk server running and events are getting delivered ontime to CRM.
Recently, we changed router/new network. After switching to new router, I see delay in events.

Is there any specific setting on router we need to do?
like we need to open certain ports or something?

version - Asterisk 18.20.2

How are events getting delivered?

I am using asterisk java SDK.
onManagerEvent we are getting events