Hi Nicks,
This can be caused by a few different issues:
[LIST=1]
- Have you used MiraConfig app on RS422 tab to configure ChA (Tied to Port 8000) to use VDCP protocol over Ethernet?
This is how things should be selected (be sure to confirm all radio buttons; and be sure to click the red "Restart Mira" button to apply any changes you make):

- Is the clip you're attempting to load via DashBoard of the same video standard as the currently operating video standard of the Mira Server itself?
Loading a clip of a different line standard is not allowed.
- Something to try once the above is confirmed:
Manually load a given clip into ChA using the Mira Explorer app.
Be sure this clip is 'cued' to the beginning, and STOP button (Blue Button) is active.
THEN use DashBoard control to simply execute the "PLAY" command for ChA.
Does the clip PLAY?
There are a few less variables to issue the PLAY command"”this is a good test of the basic VDCP communications for Mira.
#DashBoard