Email not sending because there isn't a body attached to the message

The error I'm getting is that there isn't a body and sendgrid is rejecting the email.

"Sending emails to Sendgrid service failed with error message Missing email body."

We're on Drupal 9.5.11, SimpleNews 4.0.0

The confirmation email in settings has the default.

"We have received a request to subscribe [simplenews-subscriber:mail] at [site:url]. To confirm please use the link below.

[simplenews-subscriber:confirm-url]"

The newsletter does send.