[0.13.1] 'Invalid skin.'

I recently updated my Minecraft pocket edition to 0.13.1 . Every time I join a server, it tells me that every skin is invalid, including Steve and Alex.
Promptly after I had updated, I changed my skin using an app called 'skin seed' . I was going to go on my favourite server which is 'hypixel' and play on my favourite game; 'Survival games'.
Now when I try to join, it tells me 'skin invalid' , which is prohibiting me from playing my favourite game ever!!!
I'd also like to add that none of the versions are available where you select them so I clicked a random one.
Steps to Reproduce:
1. Update Minecraft pocket edition to 0.13.1
2. ... Change skin
3. ... Go onto a server