UCS-HD Discovery fails with error 551 and 555


UCS-HD pattern steps fail with errors "551 - Authentication failed" or "555 - Session not found."

Release or Environment

All currently supported environments.


Incorrect applicative username/password combination.

The communication via the pattern to the UCS device uses http(s) requests. The username/password can be tested against the target using a POST tool of your choice.

The following would need to be passed to the chosen tool to confirm username/password (remember replace userName, password, and ip of UCS device with necessary values):

Content/Body: "<aaaLogin inName="userName " inPassword="password" />"
ContentType: "application/xml"
Charset: "UTF-8"
Target: https://<ip_of_UCS_device>/nuova

Alternatively, authentication could be tested via either Windows powershell or Linux curl commands.

Windows Powershell:

[System.Net.ServicePointManager]::ServerCertificateValidationCallback = {$true}
Invoke-WebRequest -Uri "https://<ip_of_UCS_device>/nuova" -ContentType "application/json" -Method POST -Body '<aaaLogin inName="userName " inPassword="password" />'

Unix\Linux Curl:

curl -d '<aaaLogin inName="userName " inPassword="password" />' -H "Content-Type: application/json" -X POST https://<ip_of_UCS_device>/nuova

Url path not available:

Per Cisco's "Cisco UCS Manager XML API Programmer's Guide" the url for the API should be https://<ip_of_UCS_device>/nuova. If this url is not present communications will fail.


Create applicative credential with correct username/password combination and perform discovery again. Usernames and passwords are case sensitive. If the URL is not available, contact the UCS admin or Cisco support to complete setup of the target UCS device.

Additional Information

Cisco UCS-HD document: