Selecting group for event

I did my first Zwift race tonight and was unable to select the appropriate group. Based on my w/kg, I should have raced the B group, but I could only register in A. I tried signing up for other events too, most only allowing me to sign up in A and one only allowing me to race D. (When trying to select another group, I just get a continuous little spinning wheel like it’s loading). Any thoughts?