Network working fine for me.
Try switching off, taking the SIM out, gently cleaning the contacts, reinserting it, switching on again and see if that makes any difference.
If not then try a manual scan for networks and manually reconnect to 48.
If you still have the same problem then you might want to try a replacement SIM and/or contacting 48 support for more advice (see the link in my signature below).
Hope this helps.