If you see the following error:

We’re sorry, but we cannot play the video you requested. Please try again. If the problem persists, visit the Disney+ Help Centre (Error Code 39). 

This means that the video you are trying to watch cannot be watched at this time. This could be a rights availability or internal system issue.

In our testing this appears to be due to Disney+ requiring your TV to support HDCP 2.2. for the Disney+ app to play HDR or 4K content. TVs that only support up to HDCP 1.4 may not be able to play the HDR or 4K content on Disney+.

If you have this issue on a TV that is HDCP 2.2, your SmartVU SV10 may have HDCP 1.4 forced on.
To turn that feature off go to Home > Settings > Advance Options > Force1.4 > Off

If this problem continues, please contact Customer Service on one of the three channels here: https://help.disneyplus.com