I have a website that allows visitors to fill in a form with their name, email address, and a question, and this is sent as an email message to the nominated website member.
The email messages are plain text and contain a 'Reply-To' header with the name and email address provided by the visitor. They are sent from noreply@mydomain which is managed by Google Workspaces.
Here is an edited snippet of the relevant headers:
Date: Wed, 10 Nov 2021 11:25:55 +0000
Subject: Question
From: My Business <noreply@mydomain>
Reply-To: Visitor <visitor@theirdomain>
To: Member <member@theirdomain>
When this is working correctly, the recipient receives the message from noreply@mydomain, and when they click the reply button in their email client, the reply will be addressed to the visitor. Most email clients are compliant and this arrangement has worked reasonably well for many years.
However, over the last few days a number of website members with gmail addresses are replying to the noreply@mydomain address. I have sent myself a test message through the website, and when I click the 'Reply' button on the received message, the reply is addressed to noreply@mydomain. This occurs on Gmail for web, Android and ios.
I have also noticed that gmail is no longer displaying the account name for the noreply@mydomain account. It's there in the headers, but only the address is displayed in list view and message detail view.
I have opened up older messages from 2017 (these are the most recent ones I have) and they still display and create a reply correctly. I have compared headers, and both pass SPF and DKIM. The major difference is the new message contains ARC- headers that weren't implemented in the past.
Does anyone have any ideas how I can fix this problem?