Modem crash is repeating everyday, how can I stop it?

[AC Question]

Modem crash is repeating everyday

guys, I need your help !

my Phone ( Samsung A7 SM-A700FD, Andriod 5.0.2)
is crashing everyday now, giving me black screen with the following:

:: Ramdump Case :: [0xfc]
Subsystem Crashed: MODEM!

pm8841_rev :0x0

Wait...
Done!

Modem Crash
UPLOAD MODE

so what seems to be the problem, how can I fix it, as I depend on my mobile for most of my work.

Thks