XSplit Gamecaster has options to perform comprehensive logging used for searching errors and troubleshooting.
Enabling Enhanced Logging for XSplit Gamecaster
Click on the SETTINGS tab.
Scroll down to APPLICATION SETTINGS and check Enable enhanced logging.
Recreate the issue you have been encountering then close XSplit Gamecaster after.
You can find the entire log folder through the link on the Enable enhanced logging hint.
The Log folder can be found in C:\ProgramData\SplitMediaLabs\XSplit\logs\XGC by default.
When sending the log files to the support staff, we recommend compressing the whole log folder into a .ZIP file and uploading it to a file-sharing service such as Google Drive or Dropbox.