Ironically within 10 minutes of posting I got this response from AC:

"Hello Eugene,
This is Brandon from Amazing Charts Technical Support. I am reaching out regarding your questions about the compatibility of Server 2019. Server 2019 works but has its bugs with Amazing Charts. Not enough testing has been done with AC and Server 2019 at this time. Our cloud servers currently operate on Server 2016 and function fine. Version 11 is currently in beta and is being further tested with Server 2016. I would suggest using 2016 at this point in time if you need a new server, or if you plan to upgrade keep in mind if you utilize 2019 you may experience some issues as it has not been tested to the fullest. At this time I am unsure the estimated release date of version 11 as baseline for the latest version. If you have any further questions please feel free to ask. Otherwise, have a great rest of your day!

Best Regards,
Brandon"

Gene Nallin MD solo family practice with one PA Cumberland, Md