My main profile keeps breaking and I got no clue why!

Someone please help! Every time I go to upload my new profile picture it refuses to let me it will say that it updated and it should have my new photo and then it just shows the default photo. You know the one that you get before you upload anything! I’ve tried it on both the app and on the website and it just refuse to work!!! I would love to know if there is any way to fix this :(