Recipient email address tokens

Not sure, which action you're actually using. There is Send email from Drupal core, which has a validation for the email field which expects :mail to be contained in the token name, which is what you can see as a description below the field. So, the token [user:mail] would work, but [mail] doesn't. This is a constraint that is built into the Drupal core action, which ECA can't change.

However, that action doesn't allow you to send HTML emails. Only plain text emails can be sent with that.

As you're saying that you send HTML mails, I wonder which action you're using and if that has the same field description ans validation as that from core.

What's the status on this?

I am receiving the same error message like this

action "Send HTML email" (Send HTML Email to Guest): Enter a valid email address or use a token email address such as [node:author:mail].

I used a field value token ([node:field_guest_email:value]) for mail, but its not accepting it while saving, showing that error.

Can you answer my questions from comment #2 please? I have no idea where this action plugin in coming from.