First check whether it has really expired by trying to log into the CCDC Licence Portal. If your licence has expired you will be unable to log in - please contact firstname.lastname@example.org and include your 36-character activation key.
If your computer was activated offline then you will need to repeat this process each time your licence is extended. See this FAQ on how to activate CCDC software without a direct internet connection on the system it is installed on.
There is also a known bug where the first time you run our software after your local activation has expired, you will get an error that your licence has expired, and the program will need to be left running for a few more seconds in order to allow your local activation to sync with our licence server. If you run Mercury and leave the popup about licence expiry for 10 seconds before closing it, the problem should be fixed next time you launch any CCDC program. Otherwise please contact email@example.com.