Problem with the Mailchannel Plugin

Developers Cloudflare Pages
1

Hi, I am trying to use the mailchannel plugin as described here: https://developers.cloudflare.com/pages/platform/functions/plugins/mailchannels/.

I set up the the Domain Lockdown as described here: https://support.mailchannels.com/hc/en-us/articles/16918954360845-Secure-your-domain-name-against-spoofing-with-Domain-Lockdown-.

But I always get a “Could not send your email. Please try again.” message.

Can anyone help me to figure out what is going wrong?
Is there a way to see more details in some log file or so?
Does it only work once I also set up SPF and DKIM?

4

I actually got an answer here that works for me: https://stackoverflow.com/a/77041550/518587

Why is there no proper documentation about this plugin? How to use it, how to configure it? And how to set up common features like the reply-to email?