My Minecraft skin is glitched on Multiplayer

For a while now, my Minecraft skin shows up as an Alex skin instead of the Minecraft skin that I had chosen. And this issue is happening in a multiplayer server. My skin works just fine in a Singleplayer server but not a Multiplayer server. Other players on the Multiplayer server are able to see my skin normally, but for me, I can't see my skin normally.