When using REST I get some RSSO responses such as "Redirecting to Remedy Single Sign-On" or a 401 with RSSO payload

This knowledge article may contain information that does not apply to version 21.05 or later which runs in a container environment. Please refer to Article Number 000385088 for more information about troubleshooting BMC products in containers.

This means REST requests are filtered by RSSO to prevent this 

• Go into <arserver_home>/conf and locate the rsso-agent.properties file.
• Backup and edit the file.
• Locate the excluded-url-pattern section and add the following at the end of the line |/api/.*

This is how it should look
excluded-url-pattern=.*\\.xml|.*\\.gif|.*\\.css|.*\\.ico|/shared/config/.*|/WSDL/public/.*|/shared/error.jsp|/shared/timer/.*|/shared/login_commn.jsp|/shared/view_form.jsp|/shared/ar_url_encoder.jsp|/ThirdPartyJars/.*|/shared/logout.jsp|/shared/doc/.*|/shared/images/.*|/shared/login.jsp|/services/.*|/shared/file_not_found.jsp|/plugins/.*|/shared/wait.jsp|/servlet/GoatConfigServlet|/servlet/ConfigServlet|/shared/HTTPPost.class|/shared/FileUpload.jar|/BackChannel.*|/servlet/LicenseReleaseServlet.*|/api/.*

• Save the file and restart your AR Server.