I'm trying to check a website via w3 validator, but it always fails with this error:
End of file seen without seeing a doctype first. Expected .
It's seems that it fails getting source code of the website for some reason.
However, if I add Accept-Language parameter (check this request), it will validate correctly. It's not only problem with w3 validator, for example, facebook parser, responsible for showing website preview, also doesn't see the source code.
The website uses Codeigniter php framework. Could it be the problem? Any ideas how to solve the problem?
