Markup Validation Service not working properly

To whom it may concern,

The 'Validate by File Upload' facility of your W3C Markup Validation  
Service appears to be malfunctioning intermittently.

Several times this week I've tried to validate an XHTML Basic 1.1 file  
via file upload. On one occasion it validated it correctly and said  
there were no errors, but on every other occasion (including this  
morning) it's reported that an error has been found while checking the  
document as HTML 4.01 Transitional.

The errors it records are:

1. That no character encoding has been found.

The first line of the file reads as follows: <?xml version="1.0"  
encoding="utf-8"?>.

2. That it's unable to determine the parse mode because no known  
document type could be detected.
The second and third lines of the file read as follows:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML Basic 1.1//EN"
"http://www.w3.org/TR/xhtml-basic/xhtml-basic11.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">

3. Line 1, Column 1: end of document in prolog. Underneath it says :  
'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.'

It appears that it's not reading the file. I've tried it with several  
other XHTML Basic 1.1 files and received the same response. I know the  
files are error-free because your site has validated them perfectly in  
the past.

As I said, it validated the file in question (and several others)  
correctly on one occasion during this week, but the rest of the time  
I've received the above error messages.

Sincerely,

Mike

Received on Friday, 28 May 2010 12:22:24 UTC