2.4 Ghz Signal Keeps Dropping

I would look at the app or log into the router and check "devices" just to verify which devices are connected. I would then reset the router. If no dice, I would just call tech support. 

I just received my router yesterday and everything was fine but just this evening the 2.4ghz band keeps dropping out every 5 minutes for a few minutes at a time. I only have 3 or 4 devices connected to the router. The 5ghz band sems stable. There's an older laptop which doesn't recognize 5ghz, so I need 2.4 to be stable. I'm in an area with no other wifi networks, so it's not some kind of interference. Any solutions? 

My guess would be you have exceeded the max number of 10 devices in the 2.4 band. Had this happen once I started adding smart plugs, garage door, Alexa, Chromecast, etc. adds up quick then if you have multiple phones and/or PCs as well. You can check through the Home Internet app. If this is the case there are a few workarounds. 

Having the same issue here

I've been having the same issue ever since I got T-mobile home internet about a month ago. At random times my devices will no longer be able to connect to the 2.4ghz network. The signal still broadcasts, but I will get a "cannot connect to this network" error on the device when attempting to connect.

The only solution for this is to reset the router, but this happens daily (and actually twice so far today). As happy as I am with the price, I WFH and can't be running across the house to reset my router to restore my internet service 1-2 times a day.