Hi mommy, sincethis is the first test, I reckon you shouldn't be too worried yet [even though you can't help it :( ] I read that between 2-10 % of babies will "fail" the first hearing screening but it does not mean that their is any hearing loss or anything potentially bad. Lots of the babies who need follow-up testing turn out to have normal hearing.
Some reasons that can contribute to this "failing" of hearing tests include fluid in the middle ear, vernix (waxy substance found on young babies) in the ear canal and moving around too much or crying.
Reckon you'll learn more in the review in one month's time so till then, try not too worry so much, yeah? I hope your baby is well and everything will be okay :)