Overview
This article explains how spam filtering works, what you can do to help, and how Referral Rock works to keep your program emails reaching inboxes.
What we'll cover in this article:
How Spam Filtering Works
Email providers like Gmail, Yahoo, and Outlook use automated systems to decide whether an incoming email looks trustworthy. These systems look at signals like:
Sender history: Have emails from this sender been marked as spam before? Do people engage with them or ignore them?
Content patterns: Does the email look like known spam?
Recipient behavior: Has this person interacted with similar emails in the past?
Every email provider makes these decisions differently. Gmail, Yahoo, and Outlook each use their own systems, which is why the same email can reach the inbox with one provider and land in spam with another.
Filtering is also personalized. Gmail, for example, learns from each individual user's behavior over time. If someone has previously ignored, deleted, or marked similar emails as spam, their personal filter becomes more aggressive, even for emails that reach other people's inboxes without issue. Two people at the same company can receive the same email and get completely different results.
Occasionally landing in spam doesn't always mean something is wrong. But if it's happening frequently or consistently, it's worth investigating.
If You See a Referral Rock Email in Spam
Step 1: Have the recipient move it to their inbox
In most email clients, there is a Not spam or Move to inbox button. Selecting this tells their email provider the email is legitimate, which helps future emails from the same sender reach the inbox.
Step 2: Contact support
Reach out to the Referral Rock support team using the in-app chat widget on the bottom right so we can investigate. When you contact us, please include:
Which email landed in spam: for example, the referral invitation, the reward notification, or the member welcome email.
Which email provider the recipient uses: Gmail, Yahoo, Outlook, Apple Mail, or other.
Any warning message shown: some providers display a reason such as "This message appears suspicious." A screenshot is helpful.
Whether it's affecting one person or many: a single recipient may have a personal filter; multiple affected recipients indicates something different.
The raw email file: this gives us the detail needed to diagnose the issue.
How to get the raw email file by email client:
Gmail
Open the email.
Select the three dots (⋮) in the top right corner.
Select Show original.
Copy all the text and paste it into your support message.
Outlook (desktop)
Open the email in its own window by double-clicking it.
Select File, then select Properties.
The raw header text appears in the Internet headers box.
Click inside the box, press Ctrl+A to select all, then Ctrl+C to copy.
Paste the text into your support message.
Outlook on the web
Open the email.
Select the three-dot menu (⋯) in the top right corner of the message.
Select View, then select View message details.
Copy all the text from the message details window and paste it into your support message.
Yahoo Mail
Open the email.
Select the More icon above the message.
Select View Raw Message. A new tab will open with the full message source.
Copy all the text and paste it into your support message.
Apple Mail (Mac)
Open the email.
Choose View from the menu bar, then select Message, then All Headers.
Copy the header text and paste it into your support message.
Note:The more information you can share, the faster the support team can identify what's happening.
What You Can Do to Help
Most factors that affect deliverability are on Referral Rock's side, not yours. But a few things within your control make a real difference.
Keep your contact list current
Only send to people who have genuinely signed up or opted in. Sending to old, purchased, or inactive contacts increases the chance your emails get flagged and hurts deliverability for all future sends. If you're importing a list into Referral Rock, make sure it's current and permission-based.
Write honest subject lines
Avoid ALL CAPS, excessive exclamation points, and pressure-heavy language like "Act now," "You've won," or "Free offer inside." These patterns are common in spam and will trigger filters regardless of your content. Straightforward subject lines that match what's actually in the email perform best.
Tip: You can use AI tools to check your subject lines and see if they're optimized to avoid spam triggers.
Balance text and images
Emails that are mostly images with very little readable text can look suspicious to spam filters. Make sure your email body includes real written content, not just graphics.
Ask engaged recipients to mark emails as safe
If you have active members who use your program regularly, encourage them to add your email address to their contacts or mark emails as Not spam if they ever end up in the wrong folder. Each positive action builds trust with their email provider over time.
How Referral Rock Keeps Your Emails Out of Spam
Referral Rock actively works to maintain deliverability for all program emails sent through the platform.
We monitor deliverability across all sends
We track how emails perform and watch for patterns that could indicate problems, so we can catch issues proactively, not just when a customer reports them.
We automatically manage undeliverable addresses
When an email address is no longer valid, we remove it from future sends automatically. Sending repeatedly to bad addresses is one of the fastest ways to damage a sender's reputation. We handle this so you don't have to.
Every email includes a working unsubscribe link
All Referral Rock emails include a functioning unsubscribe link. When recipients who no longer want emails can easily opt out, they're less likely to mark them as spam instead. Keeping complaint rates low is one of the most important factors in long-term deliverability. See How Members Opt Out and Manage Their Email Preferences for details on the member experience and how admins can configure the language shown on the email management page.
We invest in our sending infrastructure
We continuously work with our email infrastructure provider to maintain our sending reputation and improve the technical foundation that all program emails run on.
What's Next
If you're seeing consistent spam placement and aren't sure where to start, reach out to the Referral Rock support team using the in-app chat widget on the bottom right.
Review your imported contact list to make sure it's current and permission-based before your next send.
Do an email audit: review your subject lines to follow best practices and balance text and images within your email body.
FAQ
Why did one recipient get the email in spam but another didn't?
Why did one recipient get the email in spam but another didn't?
Spam filtering is personalized. Each email provider learns from individual user behavior over time. Two people at the same company can receive the same email and get completely different results depending on how their personal filter has been trained.
Does landing in spam occasionally mean something is wrong?
Does landing in spam occasionally mean something is wrong?
Not necessarily. Occasionally landing in spam doesn't always indicate a problem. However, if it's happening frequently or consistently across multiple recipients, it's worth contacting support to investigate.
What's the fastest way to fix a spam issue for a specific recipient?
What's the fastest way to fix a spam issue for a specific recipient?
Have the recipient open the email in spam and select Not spam or Move to inbox. This signals to their email provider that the email is legitimate and helps future emails reach the inbox.
Can I reduce spam issues by changing my email content?
Can I reduce spam issues by changing my email content?
Yes, in part. Avoid ALL CAPS, excessive exclamation points, and pressure-heavy language in your subject lines. Make sure your emails include real written content and aren't mostly images. These changes reduce the chance of triggering spam filters.
Why are program emails landing in the Outlook Clutter folder for some recipients?
Why are program emails landing in the Outlook Clutter folder for some recipients?
This is specific to corporate Outlook accounts that have a security scanner in place. When company security software scans incoming emails for safety, it modifies them slightly before they reach the inbox. That modification causes Outlook to lose confidence in the email's authenticity and move it to Clutter as a precaution. This won't affect people using Gmail, personal Outlook, or other everyday email providers.
There are two ways to fix it:
The quickest option is for the recipient to select Not Clutter the next time they see the email in that folder. Outlook will learn from that action and stop moving those emails there.
For a permanent fix, the recipient can ask their IT team to whitelist emails from Referral Rock's sending domain, which prevents the issue from occurring at all.