When I try to go into a MOP Remix Raid it tells me" You do not meet the requirements for this dungeon" I have no issue entering normal raids.
Heroic raids in remix require you to be level 70. Even for something like MSV.
I am level 70 and it keeps telling me the same thing
If you are trying to enter on your own, you need to have your legacy raid size set to 10-man. 25-man raids are not available in MoP Remix even though they were part of that expansion originally. Attempting to do so yields the error you mentioned.
I made a new character and went in with no issue, but this paladin i made can not go in. i will try to see if the legacy raid size will help