Okay, if that first things don't work for you, now you may try this second one.
The most possible cause for your problem, I thinks is the configurations in your .htaccess file.
1. Login to your cPanel.
2. Find an item called File Manager, click it.
3. Browse to your website location, usually is public_html (on left panel).
4. Find a file named .htaccess.
5. Save it on your local computer.
6. Modify it on your local computer.
7. Save (upload) it back to your website.
Before you edit the .htaccess file, please make a backup of the .htaccess file. Improper editing of this file may cause your website totally fail to run.
What things to modify in .htaccess file?
You need to examine and edit the .htaccess file, pay attention of the texts between these lines:
# BEGIN Better WP Security
# END Better WP Security
Delete any lines between the #BEGIN and #END WP Security.