When upgrading to a new version of SecureCRT (like moving to version 8.7.3), ensure that your license key is compatible. Typically, VanDyke Software provides a free upgrade path for a major version if your current version is within a certain timeframe. Check their website for specific details.
If you're experiencing issues with your SecureCRT 8.7.3 license key, there are legitimate solutions available. Here are a few: securecrt 87 3 license key fix
Your license may not be eligible for that specific maintenance release. You can check your eligibility on the VanDyke Upgrades page . When upgrading to a new version of SecureCRT