Movies pause

I suggest to investigate the cellular metrics reported by the management interface. If you have the Arcadyan or the Sagemcon gateway you will need to use the T-Mobile Home Internet mobile application to see the cellular metrics. If you post what the gateway records about the 4G LTE and 5G NR cellular signals it may become a bit more apparent. You can do speed testing with say speedtest.net or speed.cloudflare.com or fast.com to get some idea of bandwidth available. It may be there is cellular congestion and bandwidth is limited. With the limited reporting of the mobile application it is much more difficult to perform proper troubleshooting. My best guess is that there is congestion and the download speeds are low resulting in the applications stalling. If the speeds are low even though the signal is strong and clean the user load on the cells is probably being throttled and that could be.

The LED bars only provide a general idea of the cellular connectivity. The metric values provide a much better picture of the nature of the cellular connections. Of course it might be a local wireless to client communication issue not a cellular issue. If you have a client that can be connected via an Ethernet cable I would suggest testing with a wired connection vs the wireless. Check the client(s) for updates and current drivers etc… If the speed tests result in low downloads and low uploads with 4-5 bars and good to excellent metric values throttling of traffic is a probability if the end clients have solid performance on the local network. Client to client testing can be done with file transfers one to another to get a general idea of the performance of the client network adapters.