Hi! I understand you're having trouble opening the latest deals from Costco in your email. Just to clarify, are you trying to open a link within the email that leads you to the deals, or is the email itself not opening at all? Also, are you accessing these emails through a web browser on your Windows 10 device or through the Costco app?

Once I get a bit more info, I can guide you through some steps to get those deals opening properly.

Email won't open in app, mobile or desktop.Viewer.joomag.com showing as not found, error or similar

Thanks for the details! Since you're seeing a "viewer.joomag.com not found" error both on mobile and desktop when trying to open Costco's email deals, it sounds like this content is hosted on a service called Joomag, which is used for digital publications.

Let’s try a few steps to see if we can get you access:

1. Try a Different Browser: On your Windows 10 device, open the email in a different web browser like Chrome, Edge, or Firefox, instead of WebKit. Sometimes compatibility issues with the browser engine cause loading errors on external services like Joomag.

2. Clear Browser Cache and Cookies: Old cached data might be causing trouble loading Joomag pages. Clearing cache and cookies can help. On Windows 10 browsers, you can usually find this option under settings/privacy.

3. Disable Browser Extensions: Sometimes extensions can block content from loading properly. Try opening the link in incognito/private mode or disable extensions temporarily to test.

4. Check Internet Connection: Ensure you have a stable connection as partial loading or timeouts might result in errors.

5. Try Accessing Joomag Directly: Go to https://viewer.joomag.com manually in your browser to see if the site loads. If it doesn’t, there might be a service outage or restriction causing the problem.

6. Update or Reinstall the Costco App: Since you mentioned a problem with the app too, ensure your Costco app is updated to the latest version. If issues persist, uninstalling and reinstalling can clear out any corrupted files.

If after trying these you still can’t access the deals, it might be an issue on the publisher’s end with Joomag. In that case, I can assist with escalating this or offer alternatives to get the latest deals to you.

Would you like me to guide you through any of these steps now?