To reproduce: 1) Go to the user lookup next the "Organizer" field. 2) Type the search term and select "Search" 3) Either the attached system error is generated or the correct user list is displayed 4) Choose the user that you wish to invite and click "Select User(s)" 5) Either the error "You must specify a search term." is displayed or the attached exception is generated. This is being experienced on Shared Confluence Hosted instance v2.7.1 with Calendar plugin v2.6.1