In case that you are not able to log in to the administration interface, please try to take the following actions:
1.Try to log in using a different browser to see if your problem is browser-based.
4.Check the server and your computer time, both should be set correctly.
5.Check if the cookies expiration time in your browser is set to a correct value.
6.Disable your firewall if you are using one.
7.Disable all plugins and extensions installed in your browser.
If none of these options help, please contact the global administrator to check your user account and eventually reset your password.