Lost connection & Synchronization timeout

We do have a problem in a few antennas where we do have the following messages :

Hoteldefrance (station client): lost connection, not polled for too long
Ap master: disconnected, extensive data loss


Tour et taxis (station client): lost connection, synchronization timeout
Ap master : disconnected, not responding Reconnecting

We have arround 60 antennas and have those problems on 5-6 antennas but very important ones.
The problems happens every 30 min.
When the deconnection and reconnection happens we loose arround 5 pings, enought to loose the VOIP Calls ongoing.

We did already try :
Upgrading firmware : Client station and ap master are both in 5.18 (problem was also before upgrading)
Change the HW Retries to 15
Change the disconnected timeout to 8 (was 3 before)
Those changes didn’t change the situation. not better or worse.

The signal is stable at -43/-53 very good connection and arround 60 mb transfer possible both ways.
Do you have an idea what we should do ?

are you use the nv2 protocol?

For the first node, Hoteldefrance, we don’t use nv2 but the problem was solved replacing the router (old RB532)

For the second node, tour et taxis, problem is still present, and yes we do use the nv2 protocol

In order to close to the topic.
We did solve the problems using different frequencies.
We had to make a few test and finally found one without troubles.
Regards,
myFiFi