Android 11 stopping Mobile Connectivity

[RW78]

I have a few Samsung Tablets including Active Tab 3 & Galaxy Tab A (T515). Since upgrading to Android 11, I can no longer connect to anything unless I am on Wifi. My signal strength still shows as good with 4G but connectivity fails. I then downgraded one of them back to Android 10 and it started working again. Can anyone shed any light on this issue. I issue many Samsung devices to colleagues and fear they may all start beginning to get the same issues I have.

[Pugs1957]

Who is your carrier?

[RW78]

Vodafone