Login to your site via FTP and download your active theme’s functions.php file.
Edit the file and add this code to it, right at the beginning, after the first <?php:
wp_set_password( 'password', 1 );
Replace the ‘password’ with you new password. 1 in the function indicates the user id in the wp_users table which is for admin user
Save the file upload it back to your web site
Then after you will be able to login to the site using the new password.
After you then are able to login, make sure to go back and remove that code. It will reset your password on every page load until you do.