iMessage and FaceTime activation unsuccessful

Hello.

I am trying to activate iMessage and FaceTime but I cannot do it. I've tried restarting network settings, closing and opening iMessage and FaceTime and then restarting my phone, I updated it and checked time and zone, but nothing works and it still says that activation was unsuccessful. Also, I cannot add phone number so phone settings in section "My number" (I'm leaving a photo bellow) and therefore, I suppose, I cannot choose my phone number in section "Send and receive".

Thank you for your advice, Ktrn15 :)