404 Error message is not clear

Set up a new install of JP on jurassic ninja saw this 404 error in the banner - pre-connection. `/wp-admin/admin.php?page=jetpack#/dashboard`

Upon connection it disappears and remains gone when I disconnect as well.

Not sure what this error is or what caused it. Can we add more details for clarity?

Reproduce the new-install case on Jurassic Ninja and start at the /wp-admin/admin.php?page=jetpack#/dashboard entry point. Investigate the pre-connection 404 shown in the banner and compare it with the state after connection or disconnection. Done means the pre-connection error identifies what went wrong with enough detail to be useful.

Written by the indexing model from the issue text.