Access for DO app to a connection pool hosted by a separate postgres DB server

Hi Everyone, We have a nodeJS API app that runs and connects to an entirely separate postgres 12 server that was provisioned outside of the DO app but runs in the same DO account/region etc. as the app does (the DB is just not listed when you go into look at the app details).

I’ve added the “app” as a trusted source in the database config, I setup a connection pool for this server, expecting to be able to update the DB connection string in API app and see it working without issue, but it looks like the API app is not timing out trying to connect to the DB server going through the connection pool but works fine when directly connecting to it.

I’ve even tested the connection pool to make sure it’s working by connecting through my postico postgres client, so I know the details should be correct.

Is there some undocumented thing about apps not being able to connect to a connection pool for a server that’s been separately provisioned and not as part of an app?

I thought it would have no issue working as the app is clearly listed as a trusted source, but figure maybe someone could help me before I start spinning up a DB server in the app and trying it that way.

Many thanks,

Dan.