One thing I know can cause this is the antivirus. I whitelist all my new QB64 downloads. I run Windows, and can you believe it, a Windows update actually did that to my CCleaner app! It blocks it from running. On your Linux system, we can rule that out, but have you checked any anti-virus apps you may be using?
The one other weird one I had happen only once just required I reboot my system. I did a virus check first, and when it came up empty, I did a reboot, and it fixed what ever app it was back then that wouldn't start.
Pete