Possible Cause:
The link in your email is broken or contains extra characters (e.g., line breaks).

Solution:

Open MITCALC. If no license is found, a pop-up window will appear: "License not found. Would you like to enter an authorization code or link?"

Cause: Some evaluation licenses are valid for only 7 or 30 days, and the link auto-expires after the first use.

Solution: Purchase a full license. There is no way to extend a time-limited link.