There was a known issue reported for the previous Skype for Business Server 2019 eval version 2046.0. If you have installed version 2046.0 from this site, please follow these instructions to install the June 2019 update 7.0.2046.116 for Skype for Business Server 2019, Front End Server and Edge Server.

If you are downloading the eval version for the first time from this site, you do not need to install the above updates. The current eval version has already included the above fix.