Hellow there

I have small network of 1 eap and router, for the two weeks now, the one eap used for 12-16 clients has been perfoming bad by transferring data in slow speed and sometimes not transfer data until action is taken, that is either change channel, or power from 20ghz to 40ghz or by altering coverage from 20db to alternatives.

Recently (3days now) ive installed another eap 110 to assist the previous, (i thought maybe I've many clients single eap cannot afford them) and after install it, it works well but the new problem arised from the 1st eap 110 it keep disconnecting each time and reconnect again the adopt. Works for few minutes and disconnect again and readopt.

The problem rises when it disconnect clients continue to get internet but some (iphone users) experience disconnected until they reconnect again. But if the 1st AP is turned off radio, clients in the second AP (new eap110) continue well with no disconnection.

What to do to ensure the 1st EAP110 doesn't disconnect when both 2 are connected?