The activation is perfectly reliable, what is not reliable, is usually other software in your system, like a firewall or antivirus mistakenly blocking our reliable software.
And, as explained in the manual, and so many times on the forum, you should NOT use the forum to ask question about reactivation, since my next question would have been something like "your order number" or "your activation key", which cannot be discussed in public. That's why you should only use emails for any questions about orders and reactivation.