ZF7782 AP not picking uplink from ZF7782-S <100m away

[vernon_wasile]

Currently facing issues with our mesh AP's not more than 100m away.

ZF7782 getting up link from 7782-S and was working when first installed until a week ago. Mesh AP connected to AC power when switched off and on again does not pick up the 5GHz up link. 7782-S connected to our SCG200 with error reported as:
'AP rebooted because AP lost Gateway more than 1800sec'. Code 302.

Please assist if possible. Thanks

[eizens_putnins]

Just to clarify -- your mentioned AP model as 7782-S , which has 30x120 degree antenna.
Is it  possible, that even so your root AP is 100 m aside, both antennas are directed into different directions? This would result in weak RSSI and a lot of lost packets, and it can be source of many  problems --  including reboots.
So first of all -- check quality of mesh uplink (displayed in AP detail view) and test performance by Speedflex between mesh APs (must be at least 30MB/s or better, and not much lost packets).
To impove RSSI for mesh link, you can connect external 5GHz antenna, but I am not sure if than internal 5GHz antenna will be used at all on ZF7782-S (and this can hart 5GHz clients). We mostly used external directional antenna with ZF7762-S, which doesn't have internal 5GHz antenna  anyway.
With external antenna mesh works well over 600m mentioned limit (1km was tested by us on ZF7762-S with 16 db 5GHz antenna and worked just fine - 50+ MB/s performance).