@DiePoh Are you using Mesh to extend the wifi signal? Or both of the EAP have Ethernet connection? Try to create a test 5Ghz only SSID, connect your PCs to it; Then Ping from your Windows/Mac PC to...

@Remy4409 Not sure how you run the speed test but you may confirm it is 120 "MBps" or 120 "Mbps". 1Byte=8bit

Good

@ElvisV I notice that if you want to delete a whole MAC group, then this group must NOT be used by any SSID or Access Control.

@mirdragon I have one V1.6 and one V2.6 I asked tplink what does the ".6" mean and they said it's just the manufactory factory code. V1/V1.6 are the same thing. V2 adds USB Modem support. I think...

@mehmeh Try disable the VLANs on the controller, and enable again. Or remove the switch from the controller(the Forget option), then re-adopt the switch.