Found this in the obi support pages:
Log in to your OBiTALK account, select your OBi device, and check your voice service status (e.g. SP1). What is the status shown?
Log in to your OBiTALK account
Select your OBi device
Click on 'OBi Expert Configuration' located at the bottom of the page
Click on 'Enter OBi Expert'
Under 'Voice Service' tab, select the SP service where your service is configured. Navigate to the parameter 'X_UserAgentPort' and change it to a different value such as 5080 for SP1 or 5081 for SP2, and click 'Submit'.(see screenshot below for example)
Note: You will need to uncheck 'OBiTALK Settings' and 'Device Default' in order to modify the parameter.
My device is now registered with Anveo, but why did I need to make this change?