1st Method: First method is to update the URL in the database

If you have an access to phpMyAdmin, try to update the URL in the database.

• First Login cPanel, then click on phpMyAdmin under Databases.
• Select the particular wordpress database. For eg: yourusername_wrdp1.
• Then go to wp_options, click on the Browse.
• Now search for your siteurl under the field option_name.
• Click the option "Edit" Field.
• Now change the URL in the input box of option_value.
• At the bottom of page, click the "Go" button.

(or)

2nd Method: Now we need to update folder attributes.
For that follow the following steps

• Go to "/wp-admin" directory using FTP or from file manager.
• Then right click on wp-admin directory and click on File Attributes.
• Now update the value to 755 or 777 permissions and check Recurse into subdirectories if there’s an option.
• Now click OK.
• Repeat step 1 to step 4 for the directories /wp-content and /wp-includes.
• Now open your browser and try to login to WordPress admin. Press Ctrl + F5 to clear cache.

Now the issue is fixed.

A simple tip from
Ultimatecine.com