Users do not show up in conferences

When connecting to spark messenger on one computer (my work desktop), I can see the user list when I join conference rooms. However I am unable to see the user list in conferences when joining on my personal PC. This leads me to believe there is some setting on my computer blocking the user list from showing.

Does anyone know how to resolve this?

This is a known bug. There is a workaround (change to showing chat roles) in the ticket description

This has been resolved in the latest nightly build (733) Ignite Realtime: Spark Nightly Builds And the fix will also be included in the upcoming 2.7.4 release this week.