The most common causes of Add to Calendar links failing in Outlook on the web (outlook.com or Office 365 webmail) are safelinks wrapping, pop-up blocking, and browser-based calendar restrictions.

1. Outlook safelinks (most common)

Outlook wraps all external links in safelinks.protection.outlook.com for security scanning. Some calendar deep-links break when wrapped. Fix: use AddEvent's hosted links - they are designed to survive safelinks wrapping and redirect correctly to the calendar picker.

2. Pop-up blocker

AddEvent's calendar picker opens a new browser tab or small pop-up. If the browser's pop-up blocker is active, it silently blocks this. Fix: allow pop-ups from addevent.com in your browser settings (usually a prompt appears in the address bar after the first blocked attempt).

3. Outlook online calendar intercept

When clicking an Add to Calendar link in Outlook on the web, the browser may route the .ics download to Outlook's own calendar instead of the user's preferred app. Fix: use AddEvent's universal link rather than a direct .ics download - it shows a picker so the user can choose the correct calendar app.

4. Browser and OS version

Older versions of Edge or Chrome on Windows may handle calendar URL protocols differently. Test in an updated browser.

Testing tip

Open the Add to Calendar link directly in a private/incognito browser window outside of Outlook. If it works there, the issue is with Outlook's link handling rather than the link itself.