Channel selection not working for Ap100c managed in the Sophos UTM SG430

Question

We have 21 AP100c Access Points and they are managed by the UTM SG430 with Firmware version: 9.510-5 
 I can change the channel for 5Ghz into another channel, but all acces points stay default at channel 36. Even when i select channel selection to 'auto' or/and Dynamic channel, it stays on 36 when i scan the area with laptop or other devices. 
 Reboot of Access Points and UTM doesn't change the situation, does anyone have an idea?

Ronn · Accepted Answer

Hi, thanks for your reply. 
 Indeed, it is only the 5Ghz, but that's the band we use all the time. 
 We use a dense formation of Acces Points, so with all the Access Points on the same channel, we suffer a lot of wireless problems. 
 
 Hopefully an engineer of Sophos will respond to this post.

Ronn · Answer

Hi Tiddlyfish, 
 Any response yet from Sophos?