Help → About SecureCRT should show "Licensed to" with your name and no expiration (unless it's a trial).
SecureCRT uses a license key file or name/serial combination, not a simple single "serial number." A valid license consists of: securecrt 80 license key serial number fixed
VanDyke Software issues licenses for a specific major version (e.g., v8.x). A v7.x license will not work with v8.0 or higher. Help → About SecureCRT should show "Licensed to"
Entering the name exactly as provided is critical — including case and spaces. VanDyke Software issues licenses for a specific major
Even with a legally purchased license, you may see errors like:
A "fixed" license key implies a modification of the software's verification process. These modifications are rarely perfect.