FortiAP 221E - Clients Disconnecting

[Adr]

I´ve 03 221E and many rogues APs around the office...the office was with a few people only, and no reclaim about wireless, some weeks ago we´re returning the routine in the office and we had a lot of problems with disconnecting machines... users connect normal and after a while, they appear with problems, sometimes the users are connected, but with no IP (I don´t know if a little delay from windows to appear completely disconnect) The aps are upgraded, and the office is small. Some idea to fix this problem ?

I saw this message, and I don~t know if is normal ( Disassociated because sending STA is leaving (or has left) BSS)

Thanks a lot 

[Anonymous]

Hello Adr,

As per your query, the message "Disassociated because sending STA is leaving (or has left) BSS" means that the client is moving to another access point using non-aggressive load balancing.
Can you please provide with following:
- is the issue related to 5GHz or 2,4 GHz
- which mobile device is affected (android, iphone, ipad)? how many of them are affected?
- are other devices like PCs affected?

As you are using only one AP for SSID, also can you turn off ap-handoff.