Welcome back to the Community! Thank you for reaching out to us. We apologize for the inconvenience of getting that error message. It sounds like it might be a browser issue you're experiencing. To begin troubleshooting, we would recommend clearing the cache and closing the browser completely so that it can get a good refresh. You can click here to see how to clear the cache. Once you have done that, try opening up Constant Contact and see if the issue is still present.
Please let us know if you need further assistance!