Animation works but won't play in-game

Hello,

I have a massive issue with one project: litterally no animation would play in PIE or in standalone.
I have an AnimBP for my character and for the monsters, all working flawlessly, the previews are fine, even the previews in the actor blueprints are fine, the animations are playing.

Now, whenever i spawn or place an actor in the world, the animation would just freeze on the first frame of the animation and won’t keep playing.
I’ve tested the anims on another project, and they’re absolutely fine, same thing for the models.
I also imported the Unreal default character for the project templates, tried, and i couldn’t get its animation to work outside of Persona either, still freezing on the first frame whenever it is placed in the word.

I’ve tried using a single animation asset for test purposes, it didn’t work either.
I’ve also tried to tick the “Always tick pose and refresh bones” box, but it didn’t change anything.

I’m using all the default classes apart from the GameMode and the GameInstance.

Thank you very much to anyone who could help me sort this out.