If you see this error message, or if the Send Email Trigger Action is Not Firing
Please check if
1. the email/sms content for missing } or overusing {{{
2. the custom values are valid:
especially the links: List of valid Custom values
3. the email addresses are valid:
e.g. test@gmail,com with a comma as the dot
4. From field is in the format of an email address:
e.g. Change ABC company to its email like info@abccompany.com