The same issue and more here…
When aggregating manually it shows up the following message without doing anything:
Check currently scheduled feeds for new and updated posts.
Updating John Doe's Blog from <https://johndoe.blogspot.com/feeds/posts/default> ...
No posts were syndicated, no amount shown in the message above.
The second issue:
Even if all other plugins are deactivated and only FeedWP is activated, the wp-admin/edit.php returns a Internal Server Error 500.
Any suggestions?