jaypippet
There is an issue with how the Franklin T9 and T10 hotspot devices are handling their IPv4/IPv6 protocols (this is how they connect to the internet) and the Roku devices. On some on these hotspot devices, they are actually set to use IPv6-only by default.
Roku needs to have IPv4 capability enabled in the hotspot device. You can try enabling IPv4/IPv6 initially. If that doesn't work, then select IPv4-only and you should be good to go.
Basically, you just have to clone your existing APN (the Access Point Network) of your hotspot device either by logging in at TMobile or using your TMobile app. Essentially, just clone (create new APN and copy all the info for your existing APN fast.com) and keep all the settings the same, but change the "IPType" to either IPv4/IPv6 or IPv4 and then set this new APN as your default.
Below are the instructions for configuring the new APN. Restart both the hotspot device and your RokuTV after making the below changes.
-----
Instructions for changing APN can be found here. (https://www.t-mobile.com/support/devices/t-mobile-hotspot)
Look specifically under "Connections and Network", then expand "Network and APN".
Login to the WebGui and follow these instructions. Basically you need to verify IPv4 is selected after creating a new APN name.
Create a new APN (Access Point Name)
Your mobile hotspot comes pre-configured with the access point name (APN) for your network service provider. The mobile hotspot checks the APN to determine the type of network connection to establish.
Access the hotspot WebUI Manager.
Click Settings > Network Settings.
Click the Add button under the APN list. A pop-up box will appear to create new APN.
Enter the Profile Name of APN.
Enter the APN.
Enter the Username and Password.
Select Authentication Mode: PAP or CHAP.
Select IPType: IPv4 or IPv4v6.
------
Feel free to post an update or if you need more help.