Previously validated document now returns the message shown below.

Hello

I am an instructor at Humber Institute of Technology and Advanced learning
and this session I am teaching an introduction to HTML class. We make use of
your validator process and are very pleased with the results and appreciate
all the time and effort that has been spent to create this resource and make
it available . However, in the last couple of days we have been receiving
the following message when validating pages that have not been modified
since they were last validated with no errors or warnings. I was wondering
if you have had any other communication regarding this problem or is it
unique to our location.

"Line 1, Column 1: end of document in prolog This error may appear when the
validator receives an empty document. Please make sure that the document you
are uploading is not empty, and report any discrepancy."

Thank you for your time.

 

Terry Champ