@Somnus Thanks for this. I've tried moving the EAP to another room and I can connect to it, so the problem must be either the cable or the switch. Thanks for your help.

Apologies if this has been asked before. I have a network of six EAP115-walls connected to a PoE switch which in turn goes to my router. 5 of the EAPs are set up with one SSID and function as a mesh...