"We can't find any tables" bug. Hosting route error? JSON manifest format?

New here, but reasonably techie...

I've successfully connected to my MariaDB db on an AWS Ubuntu intance. But when I try to set up an App connecting to my Resource, both my main DBs are reporting "We can't find any tables in this resource. Please select another resource."

The Console is reporting:

[Warning] Parsing application manifest https://nickedinburgh.retool.com/resources/a9b8e42c-2147-452e-8bc6-e6c5ebafc289: The manifest is not valid JSON data.
That's followed by dozens of 404s.

The only clue in Network is a red error:
"error": true,
"message": "This route is only enabled for self hosted Retool instances."
which may be related to the fact that I first downloaded the self-hosting software until I discovered it needed 16gb. If this is the issue, I can't find where to reverse the setting.

Or does my DB need to return data in a specific json format? If so, where do I find details.

Any advice gratefully received!

RESOLVED (several hours later).

For anyone else suffering the same symptoms, it turns out that ReTool requires SSL if connecting to AWS using the Access Key & Secret Key IAM method. This isn't clear in the documentation!

My db installation is on a test server without SSL.

The workaround was to use username & password, where there's an option to switch off SSL on RT. Not ideal, but better than nothing.

Also, make sure the remote db user has % for host and all privileges.