Planet Payments is the 3rd party company that Peach uses to facilitate Multi-Currency transactions.
If you are making use of multi-currency functionality, take note of restriction on the transaction ID length - which can be set to a maximum of 25 characters.
A transaction with a transaction ID longer than 25 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 25 characters, and will therefore fail as above:
The merchantTransactionId should be 25 characters or less