I got hired but now it says no shift available?

I applied to Amazon this morning and I received a email about a hour ago saying “This offer is confirmation that you will be hired* as an employee of Amazon and depends on the successful completion of your background check, drug test, and all pre-hire activities.” So I went to finish my application watched some videos and clicked on my application and it says “There aren't any shift available. We will notify you via email once shifts become available. Pre-hire appointment: You must have a shift to schedule your pre-hire-appointment” WHAT??? I’m so confused did someone snatch my spot is this a bug? I was super excited and told my parents now it’s saying pretty much it don’t exist anymore!