There are 4 reasons for an invalid licence key these are listed below:
"Invalid license key. Reason: Key expired" - The licence key has expired Email Hippo trial accounts are active for 3 months. After this, your trial has expired and you will need to purchase a subscription to activate your key again.
"Invalid license key. Reason: Insufficient Quota" - Your account has run out of quota. We recommend you upgrade your subscription to the next tier available.
"Invalid license key. Reason: Invalid Key" - The licence key you have entered is not recognised by the API. Please, check you have entered the correct key.
"Invalid license key. Reason: Disabled Account" - The Email Hippo account, associated with this licence key has been disabled. Please contact support for more information.