Activate problem CS6 master collection with original product key

Hello,

I have an original version of the Adobe CS6 master collection with a original product key. I use this version now or more than one year on my Imac with version Yosemite 10.10.2.

The last days i have the problem that my product key is not valid? How is that possible??

I re enter the product key for a lot of times but i can't reactievat my product.

Please help?

Arjan.