Can no longer make calls / network gone?

Hi so whenever I try to call someone with my cell phone it says: Cellular network not available? What exactly does this mean, how can I fix it? I definitely have a credit. I have a Huawei / Android device.

The cell phone doesn't matter. Is your prepaid card still valid? Radio hole, maintenance work?

Restart the device.

Try to go into airplane mode and then out again. Alternatively restart. There are actually cases in which the cell phone virtually surrenders and no longer tries to establish a connection on its own.

Restart does not work either