Email delivery fails when responding to calendar invites

[moonmeister]

I'm having issues with Sogo responding to Calendar invites. I chatted with support briefly about his but am hoping someone in the community might have already solved this. I'm using SendGrid to relay emails. All regular emails both from SoGo and any other IMAP client work. I also confirmed Sending calendar invites via dding a calendar event in SoGo, correctly sends those invites. Only when responding to the calendar invite (Accept/Reject/Tentative) does SendGrid reject sending the message with an error:

Hi. This is the Mailer program at mail.domain.net.

I'm afraid I wasn't able to deliver your message
    "Accepted invitation: "test 2""
to the following addresses.

This is a permanent error; I've given up. Sorry it didn't work out.

Intended Recipients: <abc.123@gmail.com>
Failure Reason: Error: 550 The from address does not match a verified Sender Identity. Mail cannot be sent until this error is resolved. Visit https://sendgrid.com/docs/for-developers/sending-email/sender-identity/ to see the Sender Identity requirements

I have also confirmed sending invite responses from my phone also fails. That's connected to SoGo as well. I will admit, I don't know how these calendar apps choose to send mail, but however it is, it is in some way different than regular mail.

Support suggested that SendGrid isn't configured correctly, while very don't know what's wrong...cause every other app and domain I have works, it's only SoGo that's breaking...which to me suggests an issue with SoGo. However, in the name of trying things I authenticated the mail.domain.net domain on SendGrid just in case, this didn't help.

I will now add some mail logs from Cloudron showing successful and rejected mailing attempts, there are some minor differences, but I honestly don't understand how those could affect sending.

First, Logs from a successful email being sent to a 3rd party.

Queuing Log:

{
  "ts": 1665503392076,
  "type": "queued",
  "direction": "outbound",
  "uuid": "00278735-6322-474A-81E9-8F457E544792.1",
  "messageId": "<21-63459080-d-620c9e00@260959258>",
  "mailFrom": "<alex@domain.net>",
  "spamStatus": null,
  "rcptTo": [
    "<abc.123@gmail.com>"
  ],
  "remote": {
    "ip": "172.18.16.1",
    "port": 53624,
    "host": "01c1a130-00e5-491a-929d-c4fd612c2a63.cloudron",
    "info": "01c1a130-00e5-491a-929d-c4fd612c2a63.cloudron",
    "closed": false,
    "is_private": true,
    "is_local": false
  },
  "authUser": "alex@domain.net",
  "message": "Message Queued (00278735-6322-474A-81E9-8F457E544792.1)"
}

Successful delivery:

{
  "ts": 1665503392715,
  "type": "delivered",
  "direction": "outbound",
  "uuid": "00278735-6322-474A-81E9-8F457E544792.1.1",
  "messageId": "<21-63459080-d-620c9e00@260959258>",
  "mailFrom": "<alex@domain.net>",
  "spamStatus": null,
  "rcptTo": [
    "<abc.123@gmail.com>"
  ],
  "server": {
    "host": "smtp.sendgrid.net",
    "ip": "52.89.19.245",
    "port": 587
  },
  "response": "Ok: queued as IzMRJMtySiCKDtlwwXICRA"
}

Next Mail logs from the unsuccessful calendar response:
Queuing log:

{
  "ts": 1665503626494,
  "type": "queued",
  "direction": "outbound",
  "uuid": "59D7277F-8CF3-4FA7-BAD4-AC539A54CD0B.1",
  "messageId": "<21-63459180-11-620c9e00@260959324>",
  "mailFrom": "<alex@domain.net>",
  "spamStatus": null,
  "rcptTo": [
    "<abc.123@gmail.com>"
  ],
  "remote": {
    "ip": "172.18.16.1",
    "port": 35900,
    "host": "01c1a130-00e5-491a-929d-c4fd612c2a63.cloudron",
    "info": "01c1a130-00e5-491a-929d-c4fd612c2a63.cloudron",
    "closed": false,
    "is_private": true,
    "is_local": false
  },
  "authUser": "alex@domain.net",
  "message": "Message Queued (59D7277F-8CF3-4FA7-BAD4-AC539A54CD0B.1)"
}

bounce Log:

{
  "ts": 1665503626631,
  "type": "bounce",
  "direction": "outbound",
  "uuid": "59D7277F-8CF3-4FA7-BAD4-AC539A54CD0B.1.1",
  "messageId": "<21-63459180-11-620c9e00@260959324>",
  "mailFrom": "<alex@domain.net>",
  "spamStatus": null,
  "rcptTo": [
    "<abc.123@gmail.com>"
  ],
  "message": "550 The from address does not match a verified Sender Identity. Mail cannot be sent until this error is resolved. Visit https://sendgrid.com/docs/for-developers/sending-email/sender-identity/ to see the Sender Identity requirements",
  "mx": {
    "priority": 0,
    "exchange": "smtp.sendgrid.net",
    "port": 587,
    "auth_type": "plain",
    "auth_user": "apikey",
    "auth_pass": "an_api_key",
    "family": "A",
    "bind_helo": "mail.domain.net"
  }
}

The mailer daemon also provides "email headers" in the reject email, presumably of the email that is being rejected, again, to me all looks good, but

Received: (Haraka outbound); Tue, 11 Oct 2022 16:33:04 +0000
Authentication-Results: mail.domain.net;
	auth=pass (plain)
Received: from 01c1a130-00e5-491a-929d-c4fd612c2a63 (01c1a130-00e5-491a-929d-c4fd612c2a63.cloudron [172.18.16.1])
	by mail.domain.net (Haraka/2.8.28) with ESMTPA id 19568C7C-2C91-49DC-B44D-7365FB820E07.1
	envelope-from <alex@domain.net> (authenticated bits=0);
	Tue, 11 Oct 2022 16:33:04 +0000
From: =?utf-8?q?alex=40domain.net?= <alex@domain.net>
Content-Type: multipart/mixed; boundary="----=_=-_OpenGroupware_org_NGMime-34-1665505984.597003-5------"
MIME-Version: 1.0
Date: Tue, 11 Oct 2022 16:33:04 +0000
Subject: Accepted =?utf-8?q?invitation=3A?= "test3"
Message-ID: <22-63459b00-11-5014c880@149971544>
X-Sogo-Message-Type: calendar:invitation-reply
To: =?utf-8?q?abc.123=40gmail.com?= <abc.123@gmail.com>
DKIM-Signature: v=1;a=rsa-sha256;bh=54NCLA1YJ/EblvBtqz+0wt14xv9hjaaEZx90dGFvjPA=;c=relaxed/simple;d=domain.net;h=from:subject:date:message-id:to:mime-version;s=cloudron;b=1HIyB1PCMRYxCyM6vsx/mEybHPLeeETBgm1SvXPiPj2P4Puwyy9FjgMa/Z2GGLjBpMNnKQqETNnkNu5tw8Da6pE7ajwACyhy0S+fP2wsvhk9E5wRE7wr82hbS0sOKwzSPalh9kLBgXKymxuSmGzuqrDijc6C6Lo/B47V4=

Any help is greatly appreciated, not understanding how these messages are different, and what I need to do to fix. Thanks!