Error "We don't have credentials of all connections in tfl/tflx file" Occurs When Running a Flow From CLI and Flow is Connected to MS SQL Server

When connected to MS SQL Server data in a flow and running the flow with the command line, the below error occurs:
 

 We don't have credentials of all connections in tfl/tflx file. The following connection(s) were not found:******.***********.*******.rds.amazonaws.com

The credential file will look similar to the following when the port number is included:

{
"databaseConnections":[
{
"hostname":"******.***********.*******.rds.amazonaws.com",
"port":"1433",
"username":"*******",
"password":"*******"
}
]
}

Cause

The port number should not be included in the Credentials .json file.

There is no port information when connecting to MS SQL Server in the Tableau Prep Builder interface.