Zenfone 4 bad cellular signal after screen replacement

Dear all,

I have a Zenfone 4, which was working perfectly. A week ago I dropped it and break the LCD (benzel). I had my screen replaced by a local store. However, after the screen replacement, the signal indoor is really terrible and often no service, when the signal outdoor is still full and working normally.

I'm confused about that. Do anyone know what the problem is and how to fix it? Or any trick to improve my signal?

Thanks a lot!