421 server error NOT COOL

Running Norton 2218114 (latest version) on windows 10 64b with MS office 2016.

Have disabled the Norton add on in outlook but Norton insists that I am having a server error (which I am not  !!!!!)

When sending an email Norton continues to show a 421 Error. "Sorry this server is busy, please try again.."

Have been using Norton for 25 years, never had this before. Now it is also showing this message on my wifes PC (same config)

Support stated that it is outlooks fault, maybe, but it is norton who is reporting the error. I want to switch that off. If I switch it off in settings in Norton, I get messages from Norton that Norton needs to be fixed, arggghhhhh.

For me this can become a reason to move to something else.