I am sending mail to a distribution list. Some recipients report that they are getting the mail message twice.
When I send the message to email address separately, none of the recipients get a second copy.
I thought it could be email forwarding setup at the recipients end, e.g. company.com has their email server setup to forward email@example.com email to firstname.lastname@example.org and both names are in my distribution list, but some recipients getting double emails are the only recipient at their company/domain.
I have deleted and rebuilt my distribution list from scratch to ensure that there are no duplicates in it.
Any other ideas?