Hi,
You could try testing for a plugin conflict. You can do this by deactivating all third party plugins, and seeing if the problem remains. If it’s fixed, you’ll know a plugin caused the problem, and you can narrow down which one by reactivating them one at a time.
If that doesn’t help, try re-installing the plugin by deactivating and deleting it. Then install it back via addons > extensions.
Hope that helps