ORA Database Error Messages ORA-12566: TNS:protocol error August 6, 2015 mpbod ORA-12566: TNS:protocol error Cause: An unexpected TNS protocol error has occurred. Action: For further details, turn on tracing and reexecute the operation. If error persists, contact Oracle Customer Support. 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)