I keep getting a message that my key is invalid but I know it is not?
The license key for TemplateMailer is stored in the config.xml file referenced with the TemplateMailer system. The key is delivered via email either through a Trial or purchase from this web site. The key should be copied exactly as it is delivered between <LicenseKey></LicenseKey> in the config.xml file.
Be sure to copy and paste the key from the original email message to the config.xml. If you still have trouble, use our Contract form to email the key and we'll confirm its status.