Please check if the installed version of MAXQDA matches your license version. For example, you need to enter a MAXQDA 2020 license to unlock an MAXQDA 2020 installation. If the license is for MAXQDA 2018, the license cannot be used to unlock an installation of MAXQDA 2020.
Please also check your serial number for typing errors.
If you still receive this message, please contact the MAXQDA support.