Signal calls not working on mobile data in Pakistan – need help

Hi everyone,

I have a problem with Signal Messenger here in Pakistan:

Messages work fine on mobile data.

Voice/video calls don’t connect or ring sometimes.

Wi-Fi works perfectly.

I tried turning NextDNS on/off.

Signal’s Censorship Circumvention and Call Relay are ON.

Using a VPN fixes the problem.

It looks like mobile networks are blocking or slowing down Signal calls.

Has anyone else faced this?

Is there a way to fix it without using a VPN?

Any tips for DNS or other settings?

Thanks!