Scan stucked at 0%

Hi.
I have Avast Mobile Security 6.27.3 and every time I try to run scan my device it gets stucked on 0% indefinitely. What could be wrong?

First try to clear the app data: go to “Android Settings→Applications→Avast Mobile Security→Delete cache and user data”.
If it does not help, you can try to reinstall the app.
If that doesn’t help either, please let me know.