Version check on a URL failing from Product Manager

[kh99]

The "check failed" message happens when fsockopen fails (admincp/plugin.php, line 799). The error message should contain the errno and errstr that explains why.

Edit: actually, I guess there's "connect failed" and "not found" error messages, the second one being if it can't manage to find a version number in the response. In that case I guess the message isn't much help, but it might help to temporarily hack plugin.php to show the response.