Polarity has stopped working ... B5c

Hi everyone:
I have a 4km B5c link, and it has always worked well for me, until last week.
From the support, they have indicated the steps to follow, but I have not started yet, until a replacement unit arrives …
The solutions they have given me.
Check cable N,
Power supply
Update the equipment …

The same thing happened to someone on the forum.

The problem:
The transmitting antenna