The customer is using the OAuth Sever-to-Server credentials method via the Developer Console. The documentation
] mentions using the old JWT credentials method in order to create the Adobe IMS Technical Account Configuration.
Follow this step-by-step guide to configure experience manager assets with the brand portal.
Currently, BrandPortal is still using JWT.
Whereas OAuth server-to-server is not supported. The existing JWT-based integration will continue to work till 2024. Users can still create new JWT-based integrations until May 2024.