When viewing the Session Browser it does not display all the active sessions.
Review the filter on the Session Browser to verify that the session is not being filtered out.
The filter button is on the top of the sessions tab and looks like a little funnel with a drop down arrow next to it. If the filter is red, then there is a filter that is active. To modify the filter, click on the drop-down arrow next to the filter icon and uncheck what is filtered.