Facebook is down for required maintenance right now, but you should be able to get back on within a few minutes. In the meantime, read more about why you’re seeing this message. Thanks for your patience as we improve the site.
If you are getting above message then try login facebook after some time because Facebook has rolled your area server in maintenance. so you can try login again after some time.
Solve Login Issue after maintenance
If you still getting this message, Then clear your browser cache and try again and it will work fine or try a different browser.
Problem Faced By User During Maintenance
During Maintenance you will face login issue, Page take long time to respond, page will take a long time to load, You will see white screen after login in App and desktop Version