TeamViewer problems on Starlink connected site

ARJ

I have many projects with two PC's running TeamViewer behind a NAT router. The WAN Ethernet port of the router connects to various networks with Internet access, these networks are often running NAT themselves too.

This configuration works pretty seamlessly on 10 sites.

However, I have one new site using Starlink for the internet connectivity. This site has a weird problem where only one of the two TeamViewer clients seems to want to connect, and even that connection is unreliable. Is there something odd about Starlink? Are they doing something that a regular ADSL based ISP does differently?

Would the log files help me diagnose the problem?