Hello @RobertD8228. I'm sorry that you are seeing this error message when you are working on your email. Sometimes this error appears as the result of a browser issue. I can see from your screenshot that you are using Safari. Have you tried using a different browser to see if the error appears then? Please let us know if you are still having trouble and we can further troubleshoot from there.
Sorry to hear this! I took a look at your account and can see you currently have an open ticket with our upper level of support to further troubleshoot this experience. A member of this team will reach out to you directly with any further updates. Please let us know if there is anything else we can assist with in the meantime.