i have a network, consisting of:

1 er7206.

1 fiber optic internet provider with a 750 mbps service.

24 archer c6.

6 ex141.

2 ex220.

2 ap ubiquiti.

all connected to a 24 port 1 gb unmanaged tplink switch on several floors of building, on each floor a 5 port 1 gb switch, i updated all the routers to the last firmware version avaible, the problem is that everything worked fine until i installed 2 ex220 routers, now all the wifi routers on the floors  of the building either do not connect or disconnect after a while, at recepcion hotel i have several ubiquiti that do not suffer from this problem as well as other tplink that also have no problems,these are far from these routers that do not connect, only on the floors 6,7,8,9, the dhcp does nor reach 240 connections, i do not have a virtual networks, they are in all ap mode, everything is one the same network