So you have had different keys over the years.
Is the key from May the latest key that you purchased?
Do you see a different, old, key in the box before you try to activate it? (If so then you need to use ‘Activate new key’.
I assume that you have followed the guidance here: CCleaner Support Community
PS. As a new member you won’t be able to post any images yet, see this for why not:
Can’t post an Image or a Weblink?