SIM Card cant be activated

Hi, I received my Sim card and tried to Activate him. Everything was ok, but suddenly it shows to me the message “activation failed - try to do it in the hotline”.

I tried the hotline and they just say “wait 24 hours”.

The LTE/5G light is off, which means that there is not even a signal of the Sim there. Basically I dont know what to do.

Edit o2_Bianca: Moved from Mobilfunk zu Hause&HomeSpot to English o2 Community mobile.