Help Groundwire VOIP registers SIP via wifi, but not by cell data

[Manfred Humphries]

I use Groundwire on my G7 Power, and it has worked fine for a long time.
Now, suddenly, Groundwire will register with my VOIP provider if I am on wifi, but it will not register if I amattached via Fido (Rogers) data. The app developer says the dns is not working for his app.
Any thoughts of where it might be blocked by Android?
Thanks

 

[Dannydet]

Are you using a VPN or ad blocker?

 

[Manfred Humphries]

Not on my mobile, no.
I just tried Zoiper and Zoiper beta with the same result

 

[Manfred Humphries]

I think I found it - by accident.
I had Network Data Saver turned on.
When I turned it off, the SIP registeredt fine.