Error message Can't read from file myWebsite.com:443/swagger/docs/v1

Hi everyone, I am dealing with a peculiar validation error on our swagger UI implementation. The swagger validator is marking the website as invalid, and when you click on the validator link it returns the error message: 

{"schemaValidationMessages":[{"level":"error","message":"Can't read from file https://mywebsite.com:443/swagger/docs/v1"}]}

the strange thing is that if I browse to https://mywebsite.com:443/swagger/docs/v1 from an external computer The text of the documentation is displayed, so the url is publicly accessible. 

Any ideas?