Symptoms: The error "Setup is about to terminate. Failed to validate license. Please contact license@appeon.com for help." as shown below may occur during upgrading your Appeon to a higher version or build.
Cause: It's probably caused by that the support plan included in the license expired already.
Solution: Please follow the below steps to get the support renewed and pick up the upgrade.
Step 1: Contact ibd@appeon.com to renew the support.
Step 2: Either click the Renew Support button on the AEM Support page (AEM > Server > Product Activation > Support) to generate a support bin file or click the Activate or Upgrade License on the AEM Licensing page (AEM > Server > Product Activation > Licensing) to generate an activation bin file.
Step 3: Send the generated bin file to license@appeon.com to get a new license with the updated support date.
Step 4: Apply the new license into the AEM.
Step 5: Try the upgrade again.