SSL/TLS Certificate Expired on ajax.aspnetcdn.com CDN Resource

Question

Hello,

I’m reporting an issue with the Microsoft Ajax CDN where the SSL/TLS certificate appears to have expired, causing browsers to block asset loading from this domain.

Affected Resource URL: https://ajax.aspnetcdn.com/ajax/jQuery/*

Issue Details:

• Browsers are returning certificate errors, such as: NET::ERR_CERT_DATE_INVALID

The resource fails to load due to the expired certificate

• This breaks production web applications that rely on jQuery loaded via the Microsoft Ajax CDN. For example, the Microsoft Bot Framework is broken here https://dev.botframework.com/apps/landing-page.

Impact: This issue affects any website loading jQuery (and potentially other assets) from the above CDN domain. Users may experience broken UI functionality, JavaScript failures, and inability to interact with interfaces relying on jQuery.

Request: Please renew and re-deploy the SSL/TLS certificate for ajax.aspnetcdn.com at the earliest possible time. If the certificate has already been renewed, please advise on expected propagation time or related updates.

Thank you for looking into this.

Answer 1

Hi,

It looks like the SSL/TLS certificate issue for https://ajax.aspnetcdn.com has now been resolved by Microsoft. The jQuery URLs under:

https://ajax.aspnetcdn.com/ajax/jQuery/*

are loading again without NET::ERR_CERT_DATE_INVALID in modern browsers, and sites that rely on those assets should start working again as caches and connections refresh.

However, Microsoft’s own documentation for the Microsoft Ajax CDN includes an important production warning:

Production applications should not take a hard dependency on CDN assets. Applications should test for the CDN asset referenced, and use a fallback asset when the CDN is not available.
The Microsoft Ajax CDN has no SLA above and beyond using an Azure CDN.

Source: Microsoft Ajax Content Delivery Network (CDN) overview and the associated GitHub issue: dotnet/AspNetCore.Docs#34049.

To reduce the impact of similar incidents in the future, you may want to:

• Implement a fallback for jQuery (and other critical scripts/styles) so that if the CDN fails (expired cert, network issue, etc.), your app automatically loads a locally hosted copy or a backup CDN.
• Consider hosting especially critical assets on your own domain or an alternative CDN where you control the certificate lifecycle and availability.
• Add monitoring for CDN asset load failures in your production telemetry so you get alerts quickly when a CDN incident affects your apps.

This way, even if there’s a temporary issue with the Microsoft Ajax CDN again, your production applications will continue to function.

Answer 2

appears to be fixed, but there is no SLA:

https://learn.microsoft.com/en-us/aspnet/ajax/cdn/overview