How did you licence the software originally? Was the licence code & details emailed to you? If so can you find the original email? Great thing about gmail is I can find emails I got years ago lol.
Are you sure you are using exactly the same details? The user name & email address used must be the ones you used originally for the licence code to work.
Can't remember when customer portals were introduced but if you have one of those then all the software will be in that, ailing that you would need to contact Vectric support for help but they are unlikely to see it until Monday (uk time)