I contacted support earlier, they were not of much help. They advised that I not use a VPN or that I should only use either Chrome or Safari; or that I should file an account recovery form - even though I still have access to my account.
It did occur to me that my Norton AV might be preventing something, so I signed in with an iPad using Safari - same result.
At this point, I am resigned to either set up another separate account with my new email address, or try another software package.
