TNS Database Error Messages TNS-12566: TNS:protocol error December 17, 2020 mpbod TNS-12566: TNS:protocol error Cause: An unexpected TNS protocol error has occurred. Action: For further details, turn on tracing and re-execute the operation. If the error persists, contact Oracle Support Services. Back to previous menu https://support.oracle.com/ http://www.oracle.com/ Share this:Click to email a link to a friend (Opens in new window)Click to print (Opens in new window)Click to share on Facebook (Opens in new window)Click to share on LinkedIn (Opens in new window)Click to share on Tumblr (Opens in new window)Click to share on Twitter (Opens in new window)Click to share on Pinterest (Opens in new window)Click to share on Reddit (Opens in new window)Click to share on Pocket (Opens in new window)