Does DO play your other content ok? And have you tried hitting that "refresh" button on the right hand side of the "My Recordings" page...
Next would be to manually log out, closing all browser windows (so that your credentials aren't incorrectly held available from one of the other sessions) and then logging back in?
Often any content problems where your DVR stuff doesn't show comes down to the cache of information on DishOnline's side.. logging out, logging back in, and then refresh should make sure you're seeing the correct content .. and if still not... then there's something about those events that is not visible to DO or is in some way blocked.
VOD content I've tried to play and get told you can't playback through Dish Online ... and then I go to Dish Remote Access (yes the old one) and it plays it just fine there..
you should also try Dish Remote Access (try going in through dish.sling.com ....) if not able to get in that way use this link:
Dish Remote Access