You can try the following troubleshooting guide:
1. Make sure you have the correct date settings on your computer or phone
2. Try and log in from a computer (or phone internet browser) if you have been trying from a phone app or try a different browser if you have been doing this from a computer
3. Try and reset your password using the forgot password link (this is recommended for hacked accounts) - this can only be done from an internet browser (computer browser preferably)
4. Test if your internet browser has connection if you are failing to login form a phone app to be sure it is not a connection issue.
Please kindly resubmit including the device you are using, the email client (Gmail, Yahoo, etc) and any error you are receiving should the above troubleshooting not help.