Cellular signal boosters are actually small computers.
Like all computers, they do lock up now and again. It's rare, but they sometimes just stop working.
Before tossing a perfectly good cellular booster, why not try a simple reboot? Unplugging the booster for about 30 seconds and plugging it back in may be all you need to do to make things as good as they've ever been.
If you find that this works for you, and you find that you're rebooting more frequently than you would like, try something like the NetReset
which automatically reboots your device on a schedule you set. It works with routers, modems or anything else that could benefit from a frequent reboot. It's also a lot less expensive than getting a new cell booster, although obviously if you're to the point where you're rebooting your booster once a day you might want to consider a new one anyway.