Error: "Invalid certificate or receipt"
Please ensure that you are copying and pasting the server certificate in as a single, unbroken string, with no spaces and no unprintable characters e.g. line feeds, carriage returns etc. Failure to do so is a common reason for obtaining this error. Another is accidental trimming of characters from the end of the certificate when copying/pasting. Also, the activation certificate from the server must match the activation request made on the client. If the client has, before importing the certificate from the server, made another activation request, then the new client certificate will not match the server certificate generated by the original activation and will have to be used to generate a new server activation request.
Delete everything at C:\ProgramData\erwin\Data Modeler\Licensing and then try to activate the license.
Note: you may not see ProgramData folder because by default at windows operating system,
hidden folders are not displayed, there are 2 ways to access the folder.
1) Press windows key + R, paste in: C:\ProgramData\erwin\Data Modeler\Licensing and hit enter
2) Navigate to C: drive, go into view tab (1), enable hidden items (2)