Bots can't be created from Xcode Server hosted repository
Solution 1:
You have got the SSH URL all wrong. You cannot use SSH simply by replacing the protocol and leave the URL in the same form as HTTPS. Here is a step by step guide for using SSH with Git on XCode Server and setting up the bots:
http://ikennd.ac/blog/2013/10/xcode-bots-common-problems-and-workarounds/
One more that is a bit newer and might be more accurate:
https://honzadvorsky.com/articles/2015-08-04-xcs_tutorials_1_getting_started/