Problem setting up High Availability

I am in the process of setting up High Availability and was able to get to the last step - starting up the secondary server. Unfortunately, the secondary server (default postgres db, linux:ubuntu) fails to start up. Looking at wrapper.log for the secondary server I see the error:

Username cannot be postgres. Hint: DB connecting user cannot be a super user. Provide a normal user credential.

The postgres database for the primary server uses the username 'postgres' and that user is a superuser. I'm at a loss on why the secondary server does not start up when the primary server has no issues with that username and privileges.

Any pointers?