What's Happening
When a URL containing a # symbol is used in an Outlook email template (OFT or EMLTPL), everything after the # is removed when the email is downloaded and opened.
This means a link like:
becomes:
The user lands on the portal homepage instead of the intended page — and any tracking parameters are lost along the way.
For general guidance on how to structure URLs correctly in email templates, please refer to URL Best Practices for Email Templates.
Why Does This Happen?
The # symbol marks the beginning of a fragment identifier in a URL. A fragment is handled exclusively by the browser and is never sent to the server. Outlook follows this same rule: when saving links, it recognizes everything after # as browser-only information and discards it.
This is not a bug in Stensul — it is a known behavior defined by the internet standard RFC 3986, and it applies to any tool or platform that processes URLs.
Tracking Behavior with Fragment URLs
When Stensul's tracking parameters are enabled, they are automatically appended to the end of each URL. If the original URL contains parameters within the # fragment, the following scenarios may occur:
Scenario 1 — Parameter duplication
The original URL includes parameters inside the fragment, and Stensul appends additional tracking parameters. This can result in duplicated parameters, which may cause the link to fail.
Scenario 2 — Fragment removal by Outlook
When the OFT is downloaded, Outlook removes everything after the #, including any parameters within it. The final URL becomes the base domain only.
What Our Testing Showed
URL Used | Tracking Disabled | Tracking Enabled |
Original link (with | ✅ Works | ❌ Stripped to base domain |
Base domain only ( | ✅ Works | ✅ Works |
Base domain + fragment ( | ✅ Works | ⚠️ Parameters added correctly but |
Original link without | ✅ Works | ✅ Works |
Key takeaway: The # character is the root cause. When it is not present, URLs behave consistently with or without tracking.
What Stensul Can and Cannot Do
| Stensul's Role |
✅ Can do | Apply tracking parameters to URLs provided by the client |
❌ Cannot do | Change how Outlook processes URLs during OFT download |
❌ Cannot do | Automatically fix or restructure URLs containing |
❌ Cannot do | Prevent Outlook from stripping the fragment from the link |
The behavior occurs at the Outlook level, after the email leaves Stensul. It is outside the scope of what any email building tool can control.
Recommendations
Always implement clean redirect URLs — short links without the # — that redirect users to the correct destination within the portal (for example, using a /go/ structure).
This ensures the links work reliably across email clients, including Outlook.
Please note that this change must be implemented on the client’s server side, as it cannot be configured within Stensul.
Quick Reference
Situation | What to Do |
Campaign uses portal links with | Disable tracking parameters for that campaign, try to implement direct links without # |
Link works in browser but breaks in OFT | Check if the URL contains |