Validator availability

Hello.

My webmaster friends tell me that W3C has a realy handy tool that all
website owners should use for test and validation..

I check the site http://miryabluecruise via http:// or https and am get the
following error, 500 can not connect to www.miryabluecruise.com
<http://www.miryabluecruise> :443

I had check and validated 2 days ago and had no problem, but today when I
click the footer backlink logo it is not working.

When I delete the .htacces file it validates, but when I upload it back we
see the error.

I have also double checked the deny ip's to make sure that was not a
blocking to bot.

Other than that am I doing anything wrong.

Thanks for your help.