What should I keep in mind when I set up e-mail forwarding of invoices?

In this article you will find tips for setting up email forwarding.

Outlook/Microsoft offers the option of forwarding an e-mail as an attachment in a new e-mail. This ensures that your e-mail is not categorised as spam on the basis of an incorrect certificate
Do not use mail distribution lists
Contact your email administrator to set up forwarding correctly. They can usually help to further optimise the setup according to the following technical tips
Make sure that external e-mail forwarding is permitted
Keep an eye on server customisations
Contact your responsible email administrator to set up the forwarding correctly. They can usually help you to further optimise the setup according to the following technical tips

It is recommended to set up SPF and DKIM email authentication for your domain
Avoid changing the headers and message body in forwarded messages. If changes are made, the email may be categorised as spam
The following changes may prevent the DKIM check from being performed successfully: Changing MIME boundaries, changing the message subject, third-party software that changes the message body, extending message recipients with LDAP and changing the subject and other headers that are protected by the DKIM signature domain (including To, Cc, Date and Message ID)
Add an ARC header to forwarded messages to reduce the likelihood of forwarded messages being rejected or marked as spam
Make sure the email address the email was sent to is correct
Check whether the email has been sent or whether it is in the outbox
Check whether a spam filter or authorisation list is preventing the email from leaving the outbox
Check with your mail administrator whether other sending restrictions are preventing the email from leaving the mailbox (example: maximum number of emails sent)
Ensure that forwarding is set up so that SPF, DKIM and DMARC do not indicate spoofing by adjusting your DKIM entries so that they match the DKIM key of the forwarded emails and avoid using LDAP or other changes in the email header that could interfere with DKIM checks

Change the sender so that it refers to your forwarding domain
Make sure that the SPF record of your domain contains the IP addresses or domains of all servers or services that forward emails for your domain
Use third-party products or services to recognise spam messages and prevent them from being forwarded
Use a unique domain or IP address for the forwarding of messages
Avoid changing the headers and message body in forwarded messages. If changes are made, the email may be categorised as spam