I sounds like Constant Contact support is dodging the issue because this thread is a year old, and it wouldn't take that long to get with google and figure this out. According to google, the problem is that Constant Contact inserts "via" in the sender address info. "your_email_address" via auth.ccsend.com Google says that if you send messages using a bulk mailing vendor or a third party affiliates, check out Gmail's Bulk Senders Guidelines, including: Publish an SPF record that includes the IPs of the vendor or affiliates which send your messages. Sign your messages with a DKIM signature that is associated with your domain. Make sure the domain in the "From:" address matches the domain you're using to authenticate your emails. Can we please get some help with how to do this from Constant Contact support?
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