I'm trying to get Apex debugging working in VS Code, following instructions here. When I launch the debugger I see a popup
You exceeded your licensed number of debugging sessions. Please end other sessions or purchase more. even though I believe I have a license and there are no other debugging sessions.
The debug console shows:
Connected to Streaming API channel /systemTopic/ApexDebuggerSystemEvent. Connected to Streaming API channel /systemTopic/ApexDebuggerEvent. Disconnected from Streaming API channel /systemTopic/ApexDebuggerSystemEvent. Disconnected from Streaming API channel /systemTopic/ApexDebuggerEvent.
My scratch org states
Your org doesn't have any active Apex Debugger sessions and my DevHub is a production org and states
Your child orgs aren't using any Apex Debugger licenses. You have 1 license available.
What am I missing? Is there anything I can do to debug this issue further?