Lost HR "nos ignal"

Hello guy’s,

i’m new zwifter, 15 Days, it’s so fun, but i h’ave a problem: companion connect with my HRM and my powerckrank(Power2max) but aftre, when i ride, zwift lost my HRM.
I return to window for connect, and HRM is connect but “no signal”…

My HRM is new (2 days) it’s a Bryton.
My Powercrank is a Power2max (power + rpm)
I use zwift companion on a smartphone (android 7.0)
I use a PC on linux with “wine” .
no ERG

I ha ve no problem with powermeter… the first day with my HRM no problem… but now always “nos signal” sometimes on the ride, it’s ok, and sometimes lost… it’s crazy.

if someone can help me
Thank’s

Charly