3cx problem with replacing license key

[DPFULL]

I have reinstalled my FDQN and tried to replace the license key.However I´ve got the following error :"The installed license key cannot be replaced with this key because the key is disabled or has already been replaced. Contact your Partner" Can anybody help me ?

 

[TheodorosG_3CX]

This will require to be checked from our Customer Care department. You may use the contact form and contact the relevant department from here.