Replies to e-mails not linked to document

When I send e.g. a sales invoice, the e-mail is sent by sales@domain.com and when the customer replies to the e-mail, it is shown in the Communications List, but it isn’t linked to the Sales Invoice document.

I assume this is because the reply-to address in the e-mail sent by ERPNext is also sales@domain.com. When the customer sends an email to the address that includes the Sales Invoice number (e.g. sales+Sales%20Invoice+ACC-SINV-2022-0001@domain.com), the received email gets correctly linked to the Sales Invoice.

Is there a setting such that the reply-to address includes the document number so replies by the customer automatically get linked to the correct document?

Hello Brontos

As I’ve been told, the linking works through the “message-id” in the email headers.

Any chance you are using office365?
Because we have issues with that too.

Interesting. We are not using office365; in the tests I did I was sending e-mails to/from my personal gmail address. But we use AWS to send e-mails from ERPNext, it may be possible that it modifies the headers. I will dig into it more.

The issue was using the Amazon SES SMTP server for sending e-mails. We changed to google (smtp-relay.gmail.com) and it works as expected now. The gmail SMTP server does not modify the Message-ID in the header, while Amazon SES does.