All cellphone can see the SSID, can connect to it, can get ip address from the dhcp in TP-link switch can reach internet, but it disconnecting from SSID in few seconds and keep flapping, however no is

Hello Team, We have 25 EAP225, everything was working fine wiht no issues. We treid to setup portal and to do that, the sMB recomended us to upgraede our EAP225 to 2.6.1, the problem now our clients c