Connect Teamcity running on server to Youtrack on cloud

Hello!

I have been trying for hours to look for a solution about how to connect teamcity (which is running on our server accessible from the outside via IP aswell as DNS) to youtrack, running on cloud, where we already have 3 sprints made. I followed this manual: https://www.jetbrains.com/help/youtrack/standalone/Integration-with-TeamCity.html#define-mapping 

But after trying it, I always get the message:"There are no TeamCity server connections available in your system. Contact your system administrator." and I have not found a way how to connect to such a remote Teamcity instance.

Is there a way how to achieve this? Thanks a lot in advance

Jan Cegin