As part of the iDEAL TransactionResponse, the Issuer has provided an IssuerAuthenticationURL to which the user is to be redirected. This URL will lead the user to the banking pagesa in which the user can authenticate the iDEAL payment.
These IssuerAuthenticationURL contain parameters seperated by an "&" or "&". The IssuerAuthenticationURL look something like this: https://www.issuingbank.eu/ideal?random=1Y98dHjPwe2qq3s&trxid=0001000000000001
It is important that the provided URL is used for the redirect without adjusting any of the content! This includes any encoding of the URL before using it for the redirect, as this may break the URL.