I had the same problem in 2012, that the re-register link wouldn’t work.
Although I have been getting regular updates, the Avast window showed that I was not connected to an account.
In 2012 I was recommended to wait until less than 14 days left to re-register, which I did this time - 13 days. It didn’t work then, and it didn’t work this year
I had to get a licence key emailed to me, as I did last year.