Please help, Skyriding question

So one of my friends returned to wow after leaving for a while. They are lvl 70, so they finished the dragonflight expansion. Character is not boosted. They can’t do skyriding. They have all the abilities unlocked except the bronze timelock one, which shouldn’t affect them . When the turn on the skyriding ability none of they’re mounts fly. So they’re stuck using the old school flying. What should they do?

I might be wrong but during Dragonflight we had a quest to unlock dragonriding/skyriding not sure if its still needed but you can have him look for it

they completed that when they did the Dragonflight expansion
They have multiple of the dragons from that xpac

Which mounts specifically?

Some mounts do not have the ability to Skyride.

Did they do the entire quest chain its a tutorial for all of dragonriding/skyriding. The only other thing I could find during my quick look was someone else having this issue 2 months ago saying that making a new character fixed the issue and unlocked skyriding properly.