Actually you need to either post them on Twitter/X, https://catbox.moe/ , or Youtube if it quality is high (nor recommended for start), or, E621.net even though their "Quality Requirement" is outrageous, or you may try Newgrounds. FA can't host videos, unless they are gif. You can post a preview pic and then giving links to the actual site hosting your videos, like I do.

I see. Thank you. And you are right. E631 quality requirement is unfair. I upload my video there and it got deleted because of the quality thing. I am glad that this place isn’t like that.

https://www.furaffinity.net/view/53220537/