Redshift connection error port 16455 ?

I am getting an error when connection to Redshift about port 16455? Not sure what that port is needed for?

I was able to connect dbt Cloud through SSH to Redshift yesterday and execute queries.
But, today, I am getting the following error:

Opening a new connection, currently in state init
Redshift adapter: Connecting to Redshift using 'database' credentials
Postgres adapter: Got a retryable error when attempting to open a redshift connection.
Postgres adapter: Error running SQL: with
Postgres adapter: Rolling back transaction.
Timing info for rpc.warehouse.request (execute): 2023-03-16 15:53:01.286054 => 2023-03-16 15:53:01.287892
On rpc.warehouse.request: No close available on handle
Got an exception: Database Error
  could not connect to server: Connection refused
  	Is the server running on host "" and accepting
  	TCP/IP connections on port 16455?

Not sure why dbt is trying to connect to port 16455?

Restarting the dbt Browser IDE fixed the issue. But curious to know what this port is for or why I was seeing this error?