You get a license as a service for a certain period of time. When it expires you need to prolong it to continue using software.
To prolong a license go to "Purchased license" or "State of services" - "Show licenses". You will see your license list. Click "Prolong the service" for the license you would like to prolong. In the next window choose the term of prolonging and click "Prolong".
Ensure to have enough money on your account to prolong a license