1.) You don't need a license key. Follow the instructions in the EndNote installation manual in order to avoid being asked for a license key.
https://lib.uwc.ac.za/wp-content/uploads/2023/10/Installing-EndNote.pdf
2.) You need to download the EN21Inst.msi and the License.dat files and place both files in the same folder in order for the installation to work
University of the Western Cape,
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Tel: 021 959 2946