If youre having trouble logging into your Facebook account from your Facebook app: Make sure that you have the latest version of the Facebook app, or delete the app and then reinstall it. Try logging in from a mobile browser (example: Safari, Chrome).
Why does it say my username or password is incorrect?
It may show up even if the user hasnt even tried to enter a username or password. According to Windows enthusiasts, the “The username or password is incorrect” at the login screen occurs due to the enabled “Use my sign in info to automatically finish setting up my device after an update or restart” option.
How do I fix login problems?
Fix login issues on websites that require a username and passwordEnable cookies for the website.Clear history for that site.Clear all cookies and the cache.Check add-ons.Security application is blocking cookies.Remove corrupt cookies file.