You are attempting to use printers inside your remote sessions but they seem to be missing.
1. Ensure that the option for Printers in the Local Resources tab is enabled.
2. If you have a 64-bit Windows, you must start the Remote Desktop Manager 64-bit launcher. By default, this launcher is located in C:\Program Files (x86)\Devolutions\Remote Desktop Manager under the name remotedesktopmanager64.exe.