Remote connection to PSQL container

Hello all, I have a Raw SQL app inside of a docker container and I'm trying to get it to talk to my PSQL container and I keep getting the error in the screenshot. I've already tried logging into the PSQL container and updating its config file to allow remote connections from everywhere, but that didn't work. Please advise, if possible.

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sqlalchemy.exc.OperationalError: (psycopg2.OperationalError) connection to server at "0.0.0.0", port 5432 failed: Connection refused

Is the server running on that host and accepting TCP/IP connections?

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(Background on this error at: https://sqlalche.me/e/14/e3q8)

(testvenv)