Attempting to access the following URL
/wiki
results in a 500 Internal Server Error, which may be caused by an issue in the xwiki codebase.
Could you please investigate whether this is caused by a bug in the xwiki source code ?
Many Thanks 
This question is probably better suited for the Help / Discuss category. Anyway, without any information on the environment this is running on, it is difficult to answer anything.
My best guess is that it should be /xwiki where you deployed the xwiki.war file, and /wiki simply does not have any application deployed. Your server does not cope with that and responds with HTTP/500.