Are you able to verify if the machine that hosts Tableau Server is able to access the URL to the WDC by plugging in the WDC URL in a browser?
I am facing this same issue. Are you using the "import" or "safe list" method to whitelist the WDC? Documented here: Web Data Connectors in Tableau Server . I am using the safe list method and have already verified that the WDC will resolve in a browser from the box running the server.
Edit: Meant to also ask which WDC you're trying to connect to. Mine is the Presto WDC.
Were you able to resolve the issue?
I am getting the same error. I am using the "safe list" method to whitelist the WDC in Tableau Server. I also added WDC to the secondary safe list as mentioned in the wiki but even after server restart, it's not able to refresh the extract successfully.
Can you please advise?