no 3g or 4g after repair

Hello all. I attempted a repair on my screen on my nexus 5 , but had to open it like 6 times because of a mistake. In the end, i fixed it but now i have no 4g or 3g signal. Before the last time i opened the case i had 4g signal. I have normal phone signal and 2G when i open data. My black and white cables are well plugged. Is there anything i can try? Thanks in advance!