If your Send Email trigger action is not firing, check these four common errors to troubleshoot:
Ensure custom values are valid.
Check custom values to confirm they are correctly entered with ##{{ }} and no extras.
The From field is formatted as an email address: test@democompany.com, not a name "The Demo Company."
The To field email addresses have proper formatting e.g. test@democompany.com or scheduling@democompany.com