I work at a small startup. We have a database of contact information that is available on a subscription basis; people signup up and can download a limited number of contacts each month.
A core part of our signup is to send an activation email to the client. The email has a link back to our site. Clicking on the link activates the account and allows the client to log in.
Sometimes -- not always, but probably 20% of the time -- the client's email server will reject our activation email as spam. We see this alot with hotmail clients, and occasionally with others.
We're able to reproduce the problem. It appears to be an issue of the mail headers rather than the email content. I think it's related to the way we have our internal email configured: our email is hosted at Network Solutions, but we send the activation emails from our server at LiquidWeb. The activation email specifies a 'from' address that includes the domain that NS hosts.
My questions are: would this configuration cause email recipients to identify our email as spam? Short of moving our email server mgmt to our LiquidWeb server, is there anything we can do to avoid this issue from causing our email to look like spam?
Activation emails notoriously are identified as spam. If your reverse DNS checks out, you are not on any blacklists, and you use a reply-to address that is the same as the servername the mail is coming from, that is about all you can do. You can also try using SPF records. The reason why emails like this are flagged is because it contains a link that looks suspiciously like a tracking link and it generally includes html and can be very easily confused for spam.