Have you trapped with a plugin ? which installed recently to your website admin side and not allowing to login.
Here are easy way to get rid of this situation,
Go to PHPMyAdmin using your hosting services,
Then click on the database and click on ‘Search’ icon which is available within the phpmyadmin top menu.
Search term ‘active_plugin’ by selecting all the tables.
– The results may appear with a list which having the term active_plugin
– Browse on ‘tableprefixname_options’ table which might be showing in the results
– Click on edit option and change the value as shown below,