Hi Eric,
I’ve just come up against this issue myself. A quick poke around in the code and it looks like the issue is because cache that the aggregator uses to store the configuration of the “Import Origins” doesn’t get cleared properly when you enter your license key.
The quickest way to fix this is to run this query against the database which will remove the cache entry causing the problem, everything appears to be working after that
delete from wp_options where option_name = '_transient_tribe_aggregator_origins';