I created an alt a long time ago, before the current training sectors existed. I was away for a couple of years (a newborn baby limits game time :), and recently logged in as that alt but I found myself stuck in a training sector (Sol II A11) and unable to leave. When I try to jump I am told that I have to complete "Training III" first, but that doesn't show up on my mission list. My mission list is the usual "trading guild", "scrap mission", "basic combat", etc.

Is there a way for me to reset this or get out of this sector?

Yeah, I have to fix your character. I'll do that right now.

Edit: Your character should be located in a different sector now.