This article is for cPanel Accounts. Determine where your account is with this guide.
This indicates a fundamental access problem, which may be difficult to resolve because the HTTP protocol allows the Web server to give this response without providing any reason at all. So the 403 error is equivalent to a blanket 'NO' by your Web server - with no further discussion allowed.
By far the most common reason for this error is that directory browsing is forbidden for the Web site. Most Web sites want you to navigate using the URLs in the Web pages for that site. They do not often allow you to browse the file directory structure of the site.
You first need to confirm if you have encountered a "No directory browsing" problem. You can see this if the URL ends in a slash '/' rather than the name of a specific Web page (e.g. .htm or .html). If this is your problem, then you have no option but to access individual Web pages for that Web site directly.
You can change the setting for files and folders through the control panel, you can change global permissions and password protect directories. See the following articles for more information.
Permissions on files and directories.
How do I password protect a folder?
that this error might also be the result of your script hitting a ModSecurity ID and being blocked by the server. If this is the case please contact Tech Support so we can help you investigate it further. Support will need any necessary login data and the EXACT steps required to replicate the issue.