See this thread – the phone has some serious data and voice connectivity problems, mostly depending on which bands, most prominently LTE bands, your carrier uses:
Depending on that, there might be settings/workarounds or not. Unfortunately there is no general rule as to what works where.
(For me, in Germany, no workarounds worked properly, so I bought a small mobile LTE router and got a second SIM, with both data and voice now going through that. The phone SIM's provider needs to offer voice over wifi aka wifi calling, though, for voice to work...)