You need to install Adobe Flash Player with PPAPI.
To do so, please follow the steps below:
1- Visit https://get.adobe.com/flashplayer/ with Google Chrome browser;
2- Download Adobe Flash Player.
3- Launch the installer from your download folder.
4- After the installation, close and restart Remote Desktop Manager.
5- Create an embedded Chrome web session and use the following link https://get.adobe.com/flashplayer/about/ to verify that it works.
Remote Desktop Manager starts Google Chrome in a separate application (Embedded32.exe) and then re-parents the application inside Remote Desktop Manager.
To resolve this issue, you need to check the option Ignore certificate errors in the properties of the Web Browser (http/https) session.
Google Chrome Session Properties