Hello @valkyrias 

We have an instruction that should be able to help :

Why can’t I enable Remote Control on the Kasa APP?

- change router DNS to 8.8.8.8 save the settings and reboot router

- check if router firewall blocked any tplinkcloud related domain

-  check whether the router has set up "blacklist", "access control" and other similar functions to restrict Kasa devices from accessing the network. 

You may factory reset one of the plug and set it up again on Kasa app and see if fix the issue. 

How to reset TP-Link Kasa smart switch and plug?

If still the same, may I know the model of router, do you have router + extender, does plug connect to router directly? 

Please share the device Mac or TPLINK ID by private message. 

Can you share