Hi, I had a similar problem when I first installed my EAP system. Which band are you connected to? If you are using the same SSID for both bands then it is possible that you are actually moving to 2.4ghz and since the signal strength is sufficient some devices will not roam effectively. The best way I found was to lower the strength of the signal on all EAP's. Especially on the 2.4ghz band. Try to ensure they are not overlapping too much. It took some trial and error and lot of aimless walking around my house but it seems to work well now. 

EDIT. also make sure you are on the latest firmware for both the EAP and the controller.  

Thanks I will try that. I have different ssid for 2.4 and 5hz, but every thing is set to high transmission 

I've found if you do not set the loadbalancing up correctly you get crappy performance.

Use load balancing to set the level to have the access point boot you, I use -77 for 5ghz and -83 for 2.4 (but some ap's I use -78 for 2.4)

I run one ssid for both bands and have all the roaming stuff turned on also.

Personally, I had to stop using the load balancing due to some devices being rubbish at roaming. Some devices would be kicked but never roam therefore constantly reconnecting to the weaker signal and being stuck in a cycle of disconnecting. This problem may be specific to the devices I was having problems with so could work fine for others. Sonos speakers and Ring security cameras were the worst for it.