When you try to access your website you see receive a 403 forbidden error. Additionally your website error logs show an error similar to the below:
AH01797: client denied by server configuration: /home/user/public_html/index.php, referrer: https://example.com/
You may find the 403 error is shown to some but not all IP addresses.
Cause
Your .htaccess file may contain code similar to the below which is blocking your IP address from accessing your website.
This code can be added by WordPress Brute Force login protection plugins.
<FilesMatch ".*\.php|html?\css|js|jpe?g|png|gif)$"> order deny, allow deny from 10.0.1.1 </FilesMatch>
Fix
Edit your .htaccess file and remove the code which is blocking your IP address or all IP addresses from accessing your website.
Disable any WordPress brute force plugins which may be adding the code blocking access to your website.