This is never an easy question to answer and you may never get to the root of why your email is being spammed, but there are a number of things you can check.
One of the first things we do on the support desk when investigating a question of this type is we try to determine if your email is being spammed based on the content or the sender reputation or both.
So where are you being spammed?
Is it when sending emails to your network? If so then the first point of call for checking why is to ask your internal IT to check the SMTP logs and find out why the email is being rejected / spammed. If you use any 3rd party anti spam software / hardware, this should also be checked. Typically there will be a sensible messages in the log that tell you the WHY.
It may be something as simple as your network has noticed that a lot of emails have been received from your sender address which you haven't been engaging with and therefore it now views them as Spam. If it is something as simple as this then your IT team will be able to add the sender address to your networks safe list to prevent this from happening in the future.
If the problem is with external ISP accounts which you can’t check, unfortunately we can not advise exactly why they are rejecting / marking it as “spam” either. The major ISPs like Hotmail, AOL and Yahoo will let emails in but they all use their own rules for what happens to it. Some of them will allow one email in, and then reject or junk further emails because they detect the same email has been sent to the same address in quick succession. Others will simply junk an email because it has junk type content in it. The junk type content though is unique to each ISP.
You can try sending a different design from your account to the same email account. If the different design is delivered to the inbox then you know it is the content that is being spammed rather than based on the sender reputation.
Don't forget that spam filters change on a regular basis and something that was delivered last week might not get delivered this week.
Checking your content
If you suspect that you are being spammed due to content then there are three different areas within the product that can help.
Starting in the editor there is a spam check button. If some spam words/phrases are picked up try removing them.
Secondly check the spam score on the send test tab. Once the score is returned you can click to show the extended spam report, take note and make changes where you have scored highly.
Thirdly if you have the advanced inbox checker, run an inbox check. Spam information from various spam filters will be shown here, again take note and make changes where necessary.
Once you have checked the top three and made the changes where suggested, send another email to see if your email is now delivered to your inbox.
Even if your content is perfect, if the recipients complain, there’s nothing you can do.
Checking your sender reputation
If you believe that you are being spammed based on your reputation, give the awesome support team a call and they will assist on a case by case basis.