Are you attached to the internet? Haha, seriously though, are you?
Thinking you have the appropriate login e-mail and also password (as well as you're attached to the net) there's a couple of things that might be creating your problems:
Can't Log Onto Facebook
Are you getting an error message? If so, examine the Facebook help page for descriptions and fixes to known problems.
Make sure you do not have any type of extensions or antivirus programs running that are blocking Facebook.
Have you attempted getting rid of the app's cache? Most likely to Setups > Apps > Facebook > Clear Cache. If this does not work you can try clearing information as well and also as a last hope uninstalling and re-installing the application completely.
Did you register with your contact number? Make sure you enter the country code as well when logging in.
If the app is informing you to upgrade your email address, this is more than likely due to the fact that your e-mail server is labeling your Facebook emails as spam.
If you have actually lately signed up for Facebook you could need to verify your account first. If you have actually just recently altered your password, make certain you're trying to visit with the brand-new password as well as not the old one.
If you're logging in by means of a browser, ensure you have cookies made it possible for and that facebook.com is added to your list of safe websites.
Make sure you have one of the most current variation of the Facebook app for Android.