An issue does not get synchronized and appears in the troubleshooting section with the category 'Hidden Profile Email' and the message, e.g. 'Not able to lookup the user email to map it to the field 'customfield_10302 (Multi User Picker)'. Please check the visibility of email in user profile settings.' The part 'customfield_10302' identifies the internal id of the field which is affected.
The user email is hidden in the user profile and can not be retrieved by the Jira APIs. This happens when a user email passthrough is configured for the sync and the email is hidden from public in the user profile settings.
Check if you have made the user email visibility public. The following steps should be done in order to resolve this problem:
- If necessary, update the user email visibility in the user profile settings to Anyone so that It can be seen by Backbone
- After fixing the visibility trigger a resync for the affected issues, e.g. using a JQL filter like "key in (ABC-1, ABC-2)"