Please can anyone explain what it means?

Here is the email received after a 4weeks of booking an appointment with the German consulate in Lagos,

"The waiting period for appointments for the purpose of study increases each year with new registrations on the waiting list.
Many applicants change their travel plans due to the long waiting period and no longer require an appointment. This results in appointment slots not being used, since applicants do not cancel their registrations and do not appear for their scheduled appointments. In order to decrease waiting times for all applicants still interested in perusing their plans in Germany, you are required to confirm your registration within 30 days of receiving this email.
Kindly confirm that you still wish to apply for a visa for study purposes with appointment number XXXXXXXX at the German mission abroad in Lagos by clicking on the following LINK
...............htpps:............................
Any registration that is not confirmed within the deadline will be deleted irreversibly.
Thank you for helping to make the waiting time for everyone as short as possible.
Kind regards,
Embassy/Consulate General of the Federal Republic of Germany
in Lagos""

Self explanatory.

Cc: justwise, please delete thread.