WordPress uses cookies for login authentication, so the first step in troubleshooting WordPress login issues is the simplest one. Clear your browser cookies and cache.

In Google Chrome, click on the browser settings menu and then select More Tools » Clear Browsing Data.

This will launch the Chrome Settings page with ‘Clear Browsing Data’ popup displayed on the screen.

From here, you need to select ‘Clear cookies and other site data’ and ‘Cached images and files’ options.

Next, click on the ‘Clear data’ button and Google Chrome will clear the browser cache.

Also, make sure that your browser has cookies enabled. After doing that restart your browser and then try to login. This should fix the issue for most