Why isn't the image from my external URL or CDN showing up in my push notification or in-app message preview?

For an image hosted on an external URL (like your own server or a Content Delivery Network - CDN) to display correctly in Pushwoosh push notifications or in-app messages (including the preview), whoever renders the message must be able to fetch that image over the public internet.

It helps to know who actually downloads it: Pushwoosh does not host or proxy your image. The push payload carries only the URL. On iOS the Notification Service Extension downloads the content that will be shown to the user; on Android the Pushwoosh SDK does the same; in the Control Panel preview the image is fetched by your own browser. So the URL has to be reachable from ordinary devices anywhere in the world, not only from your office network.

If the image is not appearing, it's typically due to one of the following reasons:

1. Incorrect URL: Ensure the URL pasted into the message composer is accurate and leads directly to the image file, not to a web page that displays it.
2. Image Not Publicly Accessible: The image URL must be publicly accessible over the internet. If the image requires a login, is behind a firewall or VPN, or is otherwise restricted (e.g., private CDN storage), recipients' devices won't be able to retrieve it.
3. Hotlink protection: Free image-sharing sites usually block requests coming from another app or service — they treat it as hotlinking, which violates their terms. The request is refused or redirected to an HTML page, and no image appears.
4. CDN Configuration Issues:
   • Inconsistent Availability: CDN caching or propagation delays can cause the image to be temporarily unavailable or return errors (like a 404 Not Found error) intermittently. This means it might work sometimes but not others, or work for you but not for your users.
   • Access Restrictions: Your CDN might have security settings like rate limiting, signed URLs, IP address restrictions, or geographic blocking that prevent some recipients from loading the image.
5. Plain HTTP: serve the image over https://. Since iOS 9, App Transport Security is enabled by default and blocks non-secure HTTP content unless the app explicitly opts out.

Troubleshooting Steps:

• Verify the image URL is correct and loads properly in an incognito browser window, ideally on mobile data rather than your corporate Wi-Fi, to simulate public access.
• Confirm that the image hosting or CDN does not require authentication and does not apply hotlink protection.
• Check your CDN settings for any caching rules, propagation delays, firewall rules, rate limits, or IP/region restrictions that might interfere with external access.
• If in doubt, upload the image to the Pushwoosh Media store instead and use the URL it gives you.
• Always send a test message to a real device before sending to your broader audience.