Due to a number of new acquiring bank connectors, Visa and Mastercard mandates for 3DS 2.
There is a restriction for the length of the transaction ID.
If you are making use of Peach Payments, take note of restriction on the transaction ID length - which can be set to a maximum of 16 characters.
A transaction with a transaction ID longer than 16 characters will fail with the following error "transaction declined (format error) (800.100.156)"
Please see below an example of the above-mentioned` error:
Example of a POST Request that will FAIL:
This request below has more than 16 characters, and will therefore fail as above:
The merchantTransactionId should be 16 characters or less