SQL Server Reporting Services uses role-based authorization and authentication subsystems to determine which users can perform operations and access items on the report server. You can enter the username and password of the authorized user. Please check this link: https://learn.microsoft.com/en-us/sql/reporting-services/security/granting-permissions-on-a-native-mode-report-server?view=sql-server-ver16.
If you keep getting prompted for username/password when accessing the web portal, you can refer to this link: https://learn.microsoft.com/en-us/answers/questions/164528/how-to-troubleshoot-ssrs-prompting-for-user-name-p.
If the answer is helpful, please click
Accept Answer and
Up-Vote for the same. If you have any questions, please feel free to let me know.