To clear the cache, you go to the home screen, settings, system, power and then system restart. Or you can unplug the power for 60 seconds to do the same thing. Those 2 things will clear your cache and fix most memory/space issue errors. However, if it continues to have issues immediately after doing that, it is possible that your internal memory on the device or if you have a Roku with a memory card slot, the external memory card is going bad. If it is external, you can easily replace the card, if internal, then you will likely need to replace your device soon. SD cards and internal memory have a limited lifespan and when they go bad, they tend to go bad all at once.
