Did it ever work properly?
If so when did the problems start and did anything change on your phone at that time - eg software update, settings changes etc?
What make & model is your phone?
Can you post the screenshots of the errors?
Can you do a manual scan for networks? What do you get?
Have you tried switching off, taking the sim out, gently cleaning the contacts, reseating it, switching on and doing a manual scan for networks to see if that helps.
Hope this helps.