Dear autopark24,
Greetings from team eBay!
Please share details of the exact error faced by you when generating the airway bill number along with the steps that you are following. Also confirm is this issue being faced with eBay Global Shipping (EGS)? If yes, then you need to raise the issue via the "Resolution Center" within EGS : https://www.ebayglobalshipping.com/resolution-center-seller-interface
Incase you have an account manager then please connect with your respective account manager.
Regards,
eBay Team