Hisense R6 Roku TV family apps will not open, update or install

The checks in more detail

a weak or unstable connection makes channels fail to load, so move the router or use the 5 GHz band if the TV supports it, and restart the router. Check for updates in Settings, System, System update, Check now, since Roku updates the system and channels together and a missing update causes channels to misbehave. If a particular channel fails, remove it and add it again: highlight it on the Home screen, press the star button on the remote, choose Remove channel, restart the TV and add the channel again from the Channel Store, then sign in. There is a hidden command that clears the cache:

press the Home button five times, Up once, Rewind twice and Fast Forward twice, and the TV restarts, which Tom's Guide calls a secret remote shortcut. If the TV is slow overall, a Network connection reset from Settings, System, Advanced system settings can help. Make sure the TV has enough storage; Roku TVs have limited memory, so remove channels you do not use. A channel that fails for all users after an update may be a service problem, so check the service's status or social feed. Some older channels stop supporting the Roku OS version, which you can see in the channel's information.

As a last step, factory reset the TV in Settings, System, Advanced system settings, Factory reset, which erases your channels and settings, so note your logins first. If the TV freezes in every channel after a reset, the hardware may be failing and Hisense should look at it. Record the exact error text or code that a channel shows, because Roku and the channel's support team can look it up, and a code points to the cause faster than a description. Also test the channel on another device, such as a phone or laptop, to see whether the account or subscription is the issue, since a lapsed payment or an account lock produces errors that look like TV faults.