I had this issue today when installing Windows Azure Workflow in my SharePoint 2013 environment.
In my case, the error message was as follows:
System.Management.Automation.CmdletInvocationException: Could not successfully create management Service Bus entity 'WF_Management/WFTOPIC' with multiple retries within timespan of 00:02:05.5769235. ---> System.TimeoutException: Could not successfully create management Service Bus entity 'WF_Management/WFTOPIC' with multiple retries within timespan of 00:02:05.5769235. ---> System.UnauthorizedAccessException: The remote server returned an error: (401) Unauthorized. Authorization failed for specified action: Manage..TrackingId:3e0f0351-14d0-4620-b80e-c506156b6f7a,TimeStamp:9/24/2012 1:15:07 AM ---> System.Net.WebException: The remote server returned an error: (401) Unauthorized.
Other posts talk about ensuring your RunAs account uses a FQDN. E.g. email@example.com, which I had been doing. Instructions from CriticalPathTraining also say that this account should have dbcreator and securityadmin rights at the SQL level, that TCPIP should be enabled through SQL Configuration Manager, and that the RunAs account is a member of the local administrator group (which it was).
To fix this, I first went to each of the workflow databases and explicitly set the membership for the sp_content database so that it had db_owner and also was a member of the respective application roles that had been created for each database. E.g. Store.Operators and Store.Administrators in the SbManagementDB database. I then logged into the SharePoint server as the sp_content account and re-ran the Workflow configuration to join the existing farm. This time it worked!