On iOS devices, you can force close an app when it becomes unresponsive. Periodically, people will close all their apps which is unnecessary but harmless.
IMPORTANT: Do not force close the Malwarebytes app! Force closing Malwarebytes for iOS prevents iOS from periodically running our background tasks. In order to keep the protection for Call Protection and Ad Blocking updated and effective, the Malwarebytes app needs to perform these tasks periodically. These tasks run infrequently and do not consume significant resources.