problem solved.
i had recently changed my account password to a 17 character string. it seems sl only allows 16 characters max.
so when i logged in, it only looked at the first 16 characters. which matched the first 16 characters of what i THOUGHT was my password.
however, when it asked for password verification for an email address change, it looked at all 17 characters. which, of course, didnt match.
once that was understood, i easily changed my email addresss.
thanks for your help.