Hi,

The connection issue may be caused by one of the following:

1. Base URL using HTTP instead of HTTPS – If the external API only supports HTTPS, calling it over HTTP could result in a Connection Refused error. This should be updated to the correct secure endpoint.
2. Missing or incorrect dbfilter configuration – 'dbfilter ' is mainly needed when running multiple databases to ensure Odoo routes requests to the correct database. While it does not directly control outbound API calls, a wrong configuration could cause requests to be processed in the wrong database context, potentially impacting API-related workflows

Hope it helps