Using Hosted, my transaction fails on checkout with the error, "Invoice Number is required"

The current library used by the Pressero payment method Hosted, has an issue where it cannot get the invoice, or order number, from the transaction when checkcing out from the Pressero site. This can cause the transaction to fail if the requirement for the invoice number is enabled on the account.
The setting that controls if the invoice number is required needs to be disabled on the account under Settings > Payment Form > Form Field > Payment Information > Invoice No, uncheck Required for Invoice No.
We expect that this issue will be fixed in a future update to the library, but for now the setting for the Invoice Number needs to be set to not required.
There is some further detail in the thread below, please contact support if you have any trouble making the invoice number to be not required on your account.