Hi John. That's unfortunate. Weird problem specially these days where everyone's on Wi-Fi. Maybe this article can help How To Get Out Of Your Cell Phone Contract - The Ultimate Guide. Good luck!

Carl,

Tried channel 6. Only 1 other wifi on that channel.  No improvement. 

Chatted with TCL tech service. They suggested sending phones in for service.

Chatted with Zoomer (my cell provider) and they sent 2 refurbished TCL20s phones.  I found that these phones also had the same problem.  Zoomer then said this brand of phone had the problem and suggested changing the phone but wanted $$ to do so. So we will put up with phone until contract up then switch.  Sent refurbished phones back.

Will not send in phones to TCL for service since refurbished phones are no better. 

Thanks for the advice. Not sure we have anywhere to go now. 

John

Is it only the TCL 20S that's experiencing this? How about switching to other unused Wi-Fi channels? Download Wi-Fi analyzer apps then check which channel is unused. Maybe the channel you're using is congested.

Carl,

Thanks again.  

The repeater is repeating both 2.4 Ghz (2.432) and 5 Ghz (5.180) identified as such.  Tried connecting to 2.4 Ghz right next to router with no success. (channel 5, 2.432 Ghz ,  -10 dBm).

At that location connects fine to 2.4 Ghz via repeater. (-48 dBm).

Hi John. Can you confirm if your Wi-Fi extender is actually repeating 2.4 Ghz and not just 5 Ghz. I've had similar experience on an older router where I thought it's both repeating 2.4 Ghz and 5 Ghz but only is repeating 5 Ghz. I unfortunately fixed it only by replacing it with a Wi-Fi mesh.

Also try to connect to the main router's 2.4 Ghz while you're beside it.

Carl, tried your suggestions (having tried similarly before). Could not find if phones blocked on network. But phones (2 of them both TCL20s) connect ok to 5G and to 2.4G via extender but not to 2.4G at router.  Phones also display same bad connection behavior on other wifi networks. Different phones of others connect just fine to our network 2.4G directly to router and via extender as well as 5G wifi.    Thanks for the help.

Hi John. Can you try to forget the network on your phone then restart you router and also check if you accidentally blocked your TCL 20s on the networks. Reconnect after and see if anything changes.