Outlook 365 Add-in: signatures loading with delays

Description

The Outlook 365 Add-in encountered an issue where email signatures failed to load promptly for a subset of users. The delay was noticeable when users opened the email composition window, causing a degraded user experience. The issue was reported by multiple users across different regions and was traced back to internal changes in how image URLs are processed within the add-in.

Root Cause

The issue was caused by recent internal changes to the image URL processing logic in the Outlook 365 Add-in. Specifically, a new validation step for image URLs introduced unintended latency when fetching signature images from external servers.

Impact

• User Experience: Delays in signature loading when composing emails.
• Business Impact: No critical data loss or security issues.

Resolution

1. Immediate Action: Deployed a temporary workaround to bypass the new URL validation step, reducing latency for affected users.
2. Permanent Fix: Rewrote the image URL processing logic to optimize performance and remove excessive validation checks.
3. Deployment: Rolled out the fix to production after thorough testing in a staging environment.
4. Monitoring: Post-deployment monitoring confirmed that signature loading times returned to normal.