Update: All fixed and back to normal now. Please let us know in the comments if you have any problems.
Unfortunately today (24th January) we are experiencing issues with YouTube conversions. We are currently working round the clock to resolve these, however this means that at present we cannot offer YouTube conversions from our service.
Please note file conversions are unaffected.
We apologise for any inconvenience this causes, and will update this blog post with progress in fixing this issue.
The Zamzar Team