I'm using SendForensics.com and they are picking up that ISP's are flagging emails and counting it against many emails if "X-Mailer-RecptID" is in the header. It appears that this tag only shows in Interspire sent email. Since many spammers use Interspire, it hurts the rest of us.
Is yours still in there or did you remove it?
If you do a Google search for "X-Mailer-RecptID" it is mostly related to spam. So basically, all/most Interspire Email Marketer users are are sending emails with a very negative footprint.
Can we edit this? How?
Even if you will not share how, has someone already done this?