Can't connect Google Mini to T-Mobile Home Internet

Khimba29 wrote:

Actually mine is now all working as it should - Google speaker groups, thermostat, lights etc. Make sure that all of your Google home devices are using the same 2.4ghz band connection and not the 5ghz band that TMobile defaults to. Even if one speaker or device connected to Google home is on a different band then it will throw everything off. This includes your smart phone, tablet, Chromecast and/or Chromebook in my case. Essentially i use the 2.4ghz band for all Google stuff (even though Google claims it works on 5. It does but with caveats). Anything that uses your Google home should be on 2.4ghz. i have wifi bulbs and smart plugs that aren't Google but are controlled by Home so those are on 2.4ghz as well. I use the 5ghz band for everything else...my work VPN, LG TV etc. 

Thank you for your suggestion, but my speaker groups still won't function.  I moved all devices to the same 2.4Ghz network, and even deactivated every 5Ghz SSID, and still can only cast to one device at a time.  My gateway has the 1609 firmware, not the newest 0.2103.00.0338 version. Maybe I will try going back to my ASUS router, but the last time I did that in December, my download speeds dropped from well over 100 Mbps to an unusable .7 Mbps.