Tmobile home internet wont work with chromecast device

Amen.

Not connecting with Alexa is ridiculous

I was able to connect a Chromecast with Google TV via Wi-Fi to my T-Mobile Home Internet 5G Gateway today.

It failed the first time.  A proxy selection was displayed; None or Manual.   I chose None and the Chromecast proceeded to connect successfully.

I had the Chromecast forget the network so I had to reenter the password but it succeeded on the first attempt.  So I don't know if the Proxy selection had anything to do with success.

Playing a Netflix 4K HDR title with no issue.

I hooked up a wireless router to the device and connected the Chromecast to it. 

I tried to set up a new Chromecast with Google TV last night.   

It failed to download a required software update during set up when connected to the T-Mobile Gateway Wi-FI.   Also failed when I connected it to my Orbi mesh router Wi-Fi.   And failed when I connected to either my iPhone or Windows laptop Wi-Fi Hot Spot.

About ready to give up when I noticed that I could configure my laptop Hot Spot to use the 2.4 GHz band to connect to the T-Mobile Gateway.   Reconnected the Chromecast to the Hot Spot and the software download completed.

Once set up, I was able to connect to my router’s Wi-Fi.  Netflix and other streaming services worked fine. 

So it appears to me that during initial set up, the Chromecast with Google TV needs to connect to a dedicated 2.4 GHz Wi-Fi SSID.

You can't use the older chrome cast on 5g

I got the new T-Mobile home internet gateway today. My 7 chromecast devices would not work until I did this:

Long press wifi icon from pull-down to go to OS settings/wifi. Click your T-Mobile Gateway broadcast wifi. Then settings of this. Then "Manage Router". This goes to a web url. You input your ADMIN password that you set-up when purchasing your T-Mobile home internet box. Then check-box to split your wifi signal into separate 2.4Ghz and 5Ghz channels (can be same passwords for each). Now you will be able to set-up your chromecasts (audio or video). I am running my phone on the 5g wifi and it still controls the chromecasts that I set-up on 2.4G.

I have an android tv box created by Onn which is a walmart company and it will support both 5ghz and 2ghz wifi. It has chromecast built in and works perfectly.

Picked up Google Wifi and connected it to my router.  Casting works now (Chromecast and Apple Screen Share). I have Tmobile for business with a Nokia Router.  For some reason my casting devices (chromecast, apple) weren't working.