Serial number doesn't work for cs6

[mineo2010]

I have been using Creative Suite for a few years with no issues except now and then it asks for a serial number if I want to continue using it. It is annoying to see this message as it for some reason goes to a time left setting before I need to either purchase or continue on a trial basis for 30 days. I would again apply my serial number and all is good until now where it remains in this loop with no way out of it. My Adobe Account once had details of this purchase but now it doesn't show anywhere.

I don't want to purchase again when I have a legal copy which has been ok until now. What's going on???

[Test Screen Name]

You can't purchase again. If you can re-apply the serial number every 30 days, that may be your future until it stops working completely, which could happen any time.

[mineo2010]

I used to be able to just re-apply the serial number but now it seems to be in a loop, the serial number is continuously asked for over and over, it doesn't register, Why would a registered copy all of a sudden stop working for no reason?