Problem

maybe try making again?

I am guessing you may not have an available slot to run that many giveaways at once.
As you giveaway more games and they are marked as received you gain more giveaway slots.
Per the FAQ, under Creating

• Why is there a limit to the number of gifts I'm able to give away?

  We limit the number of gifts a user can create for security purposes, and to prevent a new user from potentially posting a large number of invalid gifts to the site. When you create giveaways and your gifts are received, this number will increase. At that time you'll be able to create giveaways with a greater number of copies, and more simultaneous giveaways.