Why can't my Lumia 520 detect the 3g network automatically?

[Dhiman]

cannot detect 3g network automatically, slide up problem during received a call on my lumia 520

3g network problem,slide up problem during received a call, donot detect 3g network automatically etc.

 

[Harrie-S]

Re: cannot detect 3g network automatically, slide up problem during received a call on my lumia 520

If you phone can not detect the 3G network than the 3G network signal is to weak, try to find a place with better 3G coverage.