W3C validator – why I receive Error

Hello,

I am trying to test my website: https://www.majordroid.com/

and when i input website address here at

https://validator.w3.org/checklink

I receive: Error: 403 Forbidden
why ?

What i need to do to fix this ?

besides that i contacted W3C, and they told me this:

I think your server is sniffing headers, in particular the User-Agent one, and refusing
to serve the page to the Link Checker specifically because of that.
The User-Agent sent by LC is: “W3C-checklink/4.81 libwww-perl/6.15”

You can try this yourself from the command line, using curl:

For a dummy, random UA, the page is returned okay:

curl ‘https://www.majordroid.com/’ -H ‘user-agent: foo’

When using this UA, error 403 and an error page is shown:

curl ‘https://www.majordroid.com/’ -H ‘user-agent: W3C-checklink/4.81 libwww-perl/6.15’

Most likely, it’s a rule in your .htaccess file(s), or in your firewall/proxy.

Thank you

Have a nice day

The page I need help with: [log in to see the link]