HTTP-Rest API call fails

Attempting a PUT HTTP-REST operation to update an existing F5 pool member's session state:

Updating field works properly with cURL; however, no success using Orchestrator

Orchestrator 5.5.1 and F5 networks LTM: 11.5.1

Orchestrator is configured for SSO

host: https://<load balancer mgmt IP address>/mgmt/tm/ltm

Operation: /pool/LBPool/members/<pool member name>:80

Invoke operation workflow produces:

Request URL: https://<load balancer mgmt IP address>/mgmt/tm/ltm/pool/<pool name>/members/<pool member name>:80

Body: '{"session":"user-enabled"}'  also '{"session":"user-disabled"}'

defaultContentType: application/json

output: contentAsString {"code":401,"message":"An authorization header is missing.","errorStack":[]}

How is the authorization header inserted to achieve success in making this REST API call using Orchestrator 5.5.1?

This command updates the load balancer properly using cURL so I thought it best to ask in this forum.

Thanks in advance for your help/suggestions.