I tagged this as a comment to a similar question, but the answer only applied to people hosting their own Confluence. We are having an issue where some users are not showing up in the auto-complete popup when trying to do mentions in Confluence. We use Confluence On Demand. The answer seemed to be to rebuild the search index for Confluence, but the On Demand version does not offer that as an option to the administrator. We also use JIRA, so I rebuild the system's index, but it had no effect.
Basically I'm wondering if there is a way to effectively rebuild the search index in Confluence On Demand that I as a site admin can perform. Or - do I need to write up a support ticket to Atlassian?