The first thing I'd look at is what the License Information tile in the Analytics tab shows. It's not on a dashboard by default, so you may have to edit a dashboard and drag the License Information tile onto the dashboard and then save the dashboard. Anyway, that tile should show how many licenses Blue Prism is currently consuming. Verify that the number of 'Used' is less than the 'Limit'. What this will help show is whether or not Blue Prism thinks there is a session still running as well as if there is a pending session. Pending sessions are usually the culprit since those do not get deleted even if you restart the Runtime Resource. They'll stay there forever until you discover it by doing a show all in Session Management. Note that in my screenshot below, it shows that 1 license is being consumed, but I have no running sessions. I do, however, have a pending session sitting in Control Room, which does contribute to license consumption.
The issue could of course be something more, but I'll leave it at this until we hear back from you about whether you've checked into that stuff first.
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Dave Morris
Cano Ai
Atlanta, GA
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Dave Morris, 3Ci at Southern Company