Docker Login fails through Build Feature and Command Line step, but works on Terminal

We use the Docker Support build feature successfully on several build agents. We've set up a new build agent but the connection is failing with a timeout. This also occurs when logging into Docker using a command line step.

However, we can log in successfully by opening a terminal or running docker login directly from the agent machine.

Please advise why the TeamCity Terminal would behave differently to a Command Line step.

Thanks,

Paul