Hi,
If you have your shipping costs defined like this for example:
5:5.00,10:9.00,20:16.00
up to 5 kgs: 5,00 $
5 - 10 kgs: 9,00 $
10 - 20 kgs: 16,00 $
and a client order weighs more then 20 kgs, you will get that message.
So please look at Admin - Modules - Shipping and check your shipping weights and prices there.
Regards,
Edze