SuiteSignOn (Outbound SSO) > Error 401 > Refused OAuth Timestamp

One of the reasons of Error 401 for Outbound SSO would be the refused or invalid timestamps.

Sample Error on HTTP Response:
 HTTP/1.1 401 Authorization Required
 ...oauth_problem="timestamp_refused",....

Here are some guidelines for setting the OAuth Timestamp:
 1. The timestamp is expressed in the number of seconds since January 1, 1970 00:00:00 GMT.
    - Ensure that your server time is in GMT.
    - As with PHP for example, the function "time()" will get the corresponding timestamp in seconds but will be based on the Time Zone preference of your server.
   
 2. The timestamp value MUST be a positive integer and MUST be equal or greater than the timestamp used in previous requests.

Source: http://oauth.net/core/1.0/#nonce