Hello @rockphantom ,

Welcome to our community.

Have you changed any settings recently? Aside from the random disconnections of wireless devices, is the connection of wired devices stable? Have you checked whether the wireless devices on the router or the extender are randomly disconnecting?

On the router, if only the wireless connection is unstable: 
    1) Make sure the Router is properly placed; it should be put in an open area instead of inside a cabinet or shelf.
    2) Change the wireless channel to another one. You may refer to Changing Channel and Channel Width on a TP-Link Router (new logo).
    3) Change channel width to avoid interference. For 2.4GHz wireless client devices, adjust the 2.4GHz channel width to 20MHz; for 5 GHz wireless client devices, adjust the 5GHz channel width to 80MHz or 40MHz, etc.

But if the wireless connection is unstable on the extender, please try the suggestions of What if the Range Extender keeps losing connection?