Symptom: In regions that use a date format different than the US standard MM/DD/YYYY, there may be a situation where the installer rejects the license key with a message saying "Please enter a valid license".
Solution: Manually run the following file from the setup directory: \ISSetupPrerequisites\VcRedistx64\vc_redist.x64.exe then try the installation with the same license key, and it should go through correctly.
Note: This issue should affect only the original installation disc/download. This updated installer should properly accept the license key:
https://dl.waspbarcode.com/wasp/OPI_V1.04.04_2020.02.27.004.zip
This installer can be used for a fresh install, but should not be used to update an existing installation