Unable to confirm product Licence

Erm, what is going on?

Suddenly, I'm asked to reactivate Parallels Desktop 11, even though I'm using the same Mac it was working on just a few days ago.

When I enter the code, I'm told it cannot confirm the product licence, and rather cheekily asks me to purchase another copy.

Why? Why can't I simply continue the licence I have already paid for?

Also - why am I forced to contact you via this forum - why can I not simply email you ?