@JFBro
With certain TMobile hotspot devices, you may need to clone/create a new APN and set it to IPv4 protocol.
Some of the TMobile units are being set with either IPv4/IPv6 or IPv6 by default. Technically, the first should work, but users have reported issues with this setting. IPv6 only is not supported, so Roku will not connect with that protocol.
Basically, you can either try changing your current APN to IPv4 only or create a new APN profile using same settings as the current one but make that IPv4 setting change and set this new profile as your default. Restart both the hotspot and your Roku device after making the changes and see if you can connect.
Look under the Connections and Network for "Network and APN" of the following link for instructions on creating/setting up the APN.
https://www.t-mobile.com/support/devices/t-mobile-hotspot
Feel free to post an update with the hotspot model number if still having issues.
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