Why does my oppo ax5 have no signal after multiple tries

hi im syafiqah , my oppo ax5 has no signal for a day now , normally i would on my airplane mode and it would be back to normal but it does not work just now , i had tried multiple times also tries to force restart my oppo but still i cannot get my signal back , pls do help me asap pls ! thank u so much !!! plsss , is there something wrong w my sim card ? im not really sure … or is my phone at fault ?