GSX doesn't deactivate itself "randomly". It always related to something in your hardware, sometimes updated drivers can do that. They shouldn't, since an updated driver should not change the hardware id, but apparently some of them did.
Note that, nothing in GSX or anything in our code doesn't do ANY hardware detection, neither we have any control or any say about what exactly is being checked and what exactly triggered an hardware change, this is done entirely by the Soraco/QLM licensing software, and it's a complete black box to us, like Esellerate was before.
If you are using the old Esellerate keys to activate ( the ones starting with FSDT ), try to use the new ones from Soraco ( the ones that start with an A ), both should work, but the new keys might be more firewall friendly ( firewalls can possibly cause that error ).
If your order used an Esellerate key, you can use the Self-Help site indicated on the FAQ page of this site to retrieve the Soraco key that has been associated to your old Esellerate key.