Minecraft PE not taking custom skins

I've been trying to upload a new skin to my minecraft app since the one I have now is outdated. I've tried as many ways as I could think of to get it and other custom skins to work but no matter what I do or what skin I pick, I always get the message "that's not a minecraft skin, silly". I have the same skin I wanna use on my laptop (I still play bedrock there) and it works just fine. I don't what what the problem is, it's been an issue for weeks