This article covers
Why are my transactions failing with the error “'Transaction not allowed”?
Solution
As Chargebee relies on the gateway to process these transactions, it only displays the error that is being thrown by the gateway. Hence, we would recommend you to reach out the gateway with the above error messages and the transaction as they should be able to help you get better clarity on this.
Here is the public-facing document where Braintree has listed out the reasons for these errors which we are attaching here as well.
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