Thanks for the video! I see that you are getting this from the link checker when it's checking those links.
The web server must not like the request that
CSS HTML Validator is making to check the links. Technically it's probably a server issue according to this:
https://developer.mozilla.org/en-US/doc ... Status/405
The above says that "The two mandatory methods, GET and HEAD, must never be disabled and it should not return this type of error" and
CSS HTML Validator uses those methods when link checking.
In practicality you could just make sure that those links are correct and ignore the link error. You could also tell
CSS HTML Validator to always treat those links as good using the 'Link Filters' in the
Validator Engine Options so that they don't generate bad link errors.