Please ensure that you eliminate any restrictions on weight and volume in the shipping extension settings. Additionally, verify that the address details in the FedEx extension are accurate; for instance, the country should be listed as 'US' instead of 'USA', and the state abbreviation should consist of two letters.
Note that the payment method selection is contingent upon the delivery method being chosen first. Therefore, Stripe will not be an option until a delivery method is set. For testing purposes, activate some basic delivery methods.
https://abantecart.atlassian.net/wiki/spaces/AD/pages/3702820/No+payment+at+checkout