There are two things that could be causing this problem. One is that you are changing your internet connection between uses; switching wifi networks, or changing from wifi to ethernet or vice versa. The other is that you have activated on more than 2 computers. With our products, each serial number is allowed to be activated on up to 2 computers. Past that, it may function as you are saying.
Please let me know if you are changing network connections, or have more than 2 activated computers.