Is this 72 hour activation just a for one-time use?

I was able to copy this activation key, which is valid for 72 hours, and paste it into the Manual Product Activation window to use it.

The first time, I was able to use it for 72 hours without any problems.

After 72 hours have passed, I want to use it again, so I do the same thing, but this time a window appears saying that key is incorrect and I can't use it.

Question:
Is this 72 hour activation just a for one-time use?