On the production systems of Solaris your customer (the PSU) needs to first register with Solaris and create a user account. This needs to be done only once per customer - regardless which TPP accesses the account. After this, the account(s) need to be claimed by the PSU so that we can give access via the PSD2 API. A user can claim several accounts if necessary.
The process that needs to be done by the PSU is described in the following:
To start the process, please redirect the customer to the https://my.solarisbank.de/portal.
There you and your PSU can find additional information in the FAQ section https://my.solarisbank.de/faq.