Used 4G. Switching to 2G is a workaround, but not applicable as internet connection is very slow and voice quality isn’t that good either. Curious, with 4G enabled, outgoing calls are possible.
I cannot call to my C2, so C2 don’t receive call when I try. But I can call from C2, calls are working.
I cannot understand. Both phones have 4 G.
Edit: Now I tried 3G on C2 and call was succeeded.
Edit2: C2 Says on the right up corner there is 2.5G. I wonder if there exist 2.5G. Xperia 10 lll has 4G on and calls are working normally.
Small issue, but please copy links without site tracking data. That is the part starting from “?”. It also makes them tidier, nicer for eye. Firefox even has option for that.