Problem
The overall connection works, but when creating an issue, an unexpected error occurs.
Cause
This error can have different reasons. Please check the yasoon log file for details, which can be found here:
%localappdata%\yasoon\log
Solution
Error 417 Expectation Failed
This error can occur when an older version of Apache reverse proxy is used in front of Jira. Please see this article on how to solve this issue.
Apache and mod_proxy not handling HTTP 100-continue from client HTTP 417