@Rajeshl < I was wrong with the brackets - you do need to have it as a list of strings. Once I added that it worked.

Thank you. Added to an outstanding issue.

This is something that would be helpful with a lot of the blocks. I remember similar struggles with Twilio SMS - this is the example but I belive that's not correct - Twilio requires

["+1415XXXXXXX"]

as the format. (1) a string (2) the

+

in front and (3) wrapped in a list like Email.

Good call! Feel free to add that additional context/request to the issue linked above.