An error has occured when cloning subsite.

I tried to use the WPMU Clone plugin today for the first time to clone a subsite. The status gives An error has occurred though I see the site is made in the dashboard. Though trying to reach the dashboard of the cloned site gives the Clone status screen. During the cloning my site got unreachable and unresponsive. As this is a test environment it has no further impact. Killing the clone status page made my site as my admin reachable. So I can't use the cloned subsite at the moment.