My extra deck is missing

[Lakhesh]

Hello. I'm new here.
I wonder if i am missing something, but for some reason my extra deck is missing when i have a duel. I thought i only forgot to save my deck, but it wasn't the case. I went back to deck constructor and my extra deck monsters were in my deck. I tried solo mode but it's still missing.
Am i skipping something?

Thanks in advance.