Huawei P Smart Z constantly shows only emergency calls - What about SIM card?

I bought a new OrtelMobile SIM card a month ago and wanted to put it in my new mobile phone Huawei P Smart Z since yesterday and unfortunately the whole time is on the top left: only emergency calls…

I can't call anyone and others can't call me. I entered the PIN correctly and inserted the card correctly. I checked everything again several times. I have restarted the phone, card and unplugged, all sorts, but nothing works… Therefore, I can't open Whatsapp with the number.

What should I do? What can this be? I need urgent help.

Either the sim card is not active (eg with prepaid cards, the validity has expired or your sim card can't get access to your home network / "radio hole"). But you receive another mobile network with which you can only call the 112.