ConnectionStrings not working with MCP and Jetbrains IDEs

I have a running Python script that connects via the connection string to SupaBase (Cloud), and everything works fine.
However, when I use the same connection string within the @modelcontextprotocol/server-postgres (to run it in CursorAI) or inside Jetbrains Database Tools, it can not connect at all.

MCP/Cursor gives no proper error message (“I’m still unable to access the database”), and JetBrains says “connection failed” and sometimes even “wrong password”.
But, as already mentioned, the same connection string with a Python Script and the psycopg library works.

Has anyone faced the same issue?