One of the probable root cause :
- It seems the "User email visibility" settings in your JIRA System settings is set as "hidden". Please modify the settings to "Show to logged in users only". See below screenshot for help.
- Go to JIRA Administration >> System >> User email visibility (Show to logged in users only).
- Once the settings are changed as above. Test the integration in QMetry.
- Save the settings and Refresh the attributes.