PAR initiation not working

[laurabui-a11y]

Describe the bug
Hi there, I'm having trouble with creating a PAR request in the CDR Sandbox. There is an error message that comes up saying "Error: An Error Occurred
Unable to create the Pushed Authorisation Request (PAR) with ClientId: [XXX] - Object reference not set to an instance of an object."

To Reproduce
Steps to reproduce the behavior:

1. Log into CDR sandbox
2. Click PAR
3. Click any provider
4. Set sharing duration and scope and initiate PAR
5. See error

Expected behaviour
PAR would initiate and generate a link to redirect to our open banking API to allow testing. We have created a Bruno environment / mock register to test if PAR initiation works on there which it does.

Screenshots
Added

[ACCC-CDR]

Hi laurabui-a11y,
Thanks for raising this issue and for providing the reproduction steps and error details.
Before we investigate further, could you please test using the two ACCC-managed mock Data Holders available in the CDR Sandbox?
The CDR Sandbox contains two mock Data Holders created and managed by the ACCC. These are known by the Data Holder Brand names Sandbox Data Holder - Banking and Sandbox Data Holder - Energy.
Please test using:
• Sandbox Data Holder - Banking (cf217aba-e00d-48d5-9c3d-03af0b91cb80) - (fd5dd6ea-aef0-470d-b176-ac6580782cb9)
• Sandbox Data Holder - Energy (bc144967-d6f8-47a6-8590-07caf522141b) - (55adce56-0dfb-4b9d-868d-7aa69e6eb382)

You can find more information about the differences between Sandbox Data Holders and Participant Data Holders within the CDR Sandbox resources link or here:
Frequently Asked Questions - Participant Tooling - Confluence

If you continue to experience the error after testing with the above Data Holders, could you please provide:

1. Data Recipient/Data Holder name that you're using to test
2. The date and time when testing was performed
3. A screenshot of the error received
   This information will help us investigate the issue further.

Thanks,
ACCC CDR