Share your experience!
I just bought an Xperia X and I upgraded to Nougat and now I have problems with my SIM CARD since the install I can't make phone calls and send messages, before everything worked fine. Please tell me if you are going to correct this problem with a new update!!
check you network settings, apn settings, is it according to the networks configuration?
make sure airplane mode is disabled.
set your network type to 3G only, or 2g preferred.
how did you upgrade your device? did you tried flashing the software? or did you do it using Xperia companion?
try to perform a software repair using Xperia Companion