403 Forbidden
The 403 forbidden errors would be the one as the interface below:
It would be referring to where the permission of the document root of your domain is not configured correctly or with a corrupted .htaccess
File/folder permission
According to the WordPress codex, the ideal permission for the WordPress files/folder permission are
Files: 644
Folders: 750 or 755
To amend the permission, you may utilize the FTP client eg FileZilla for the steps to amend the permission as per screenshots below:
File permission amendment
Right click on the desired file
You will see being the as the attached below
Right after, you will be able to change the permission eg 644
Folders permission amendment:
1. Right click on the desired folder
2. You will be seeing as below
3. To repeat the permission amendment to the subsequent files/folder, may click on
Choose Recurse into subdirectories
Choose Apply to all files and directories
Reset .htaccess
The .htaccess file is a basic configuration file used by the Apache web server. You can use it to set up redirects, restrict access to all or some of your site.
You may access to the File Managar or FileZilla to locate and backup the existing .htaccess. Once done, you may logon to your WordPress admin backend:
Go to Settings → Permalinks in your WordPress dashboard
Click Save Changes at the bottom of the page (you do not need to make any changes – just click the button)