@N.Bauer Hello, thanks for asking. I think you can refer to the Case 2 in the below guide to whitelist specific URLs on the C5400X for the devices: https://www.tp-link.com/support/faq/1531/ If this...

@Holy_Father You may login to the web GUI of the C4000, go to Advanced-Wireless>Wireless Settings, then you will find the Transmit Power option.

@Ghici Hi, thanks for getting back again. May I know what is the name of that application, is it connected to the A7 via LAN? We may need to test this in our lab then give you a yes or no answer,...

@Nednyl Hello, Do you still use the original power adapter? Was there any power cut or bad weather or firmware upgrading before it behaves abnormally? Try to hard reset it by holding the reset button...

@Oldmanlight I found you have also opened a ticket with our support team, and they are follow it up, please keep in touch with them, they will help you out, thanks.

@sdhb Noted, this is reasonable :)