Sometimes it wont change ur minecraft skin on minecraft.net

So i was testing on changing my skin with the alex and steve skins and when im done i go back to my regular skin witch is a evil dirt man with gloves so it didnt work i tried again it worked yesterday i heard that people couldent change there skins anymore so they had 1 skin but couldent change my friend 84841 has a skin but i said why dont change it he said i cant it wont let me If u can fix this this will be useful for the players who just cant change there skin