Certificate issue from https://uci.cdn.office.net

Brass Contributor

Hi, One of the users of a Excel Js Add-in that I've recently had published to AppSource (Copy as List) has reported getting an Anti-Virus popup every time he starts Excel.


From Avast anti-virus. The message is:


Connection to this website is not secure.

Avast has blocked access to https://uci.cdn.office.net/ because one of the issuers of the server certificate has expired.

Certificate: cdn.uci.officeapps.live.com

Issuer: Microsoft Azure ECC TLS Issuing CA 01


Indeed, if I try to browse to that URL in Chrome, I get an error:

"This server could not prove that it is uci.cdn.office.net; its security certificate expired in the last day. This may be caused by a misconfiguration or an attacker intercepting your connection. Your computer's clock is currently set to Friday 28 June 2024. Does that look right? If not, you should correct your system's clock and then refresh this page."

Does anyone know what this is? Is it related to my add-in? How do I fix it? What advice do I give to my user?



11 Replies

@CBullen same antivirus, same problem. 

problemas con avast, no reconoce certificados

@CBullen also have same issue w two clients w Kaspersky. Different tenants.

Same here with Avast One

It's not an AV problem, the certificate of the hoste is no longer valid :D



i created an exception in AVG. problem solved.

@dbugmann agreed - have advised msft as it’s one of their cdn fqdns, I believe.

@mratajczak How do I create the exception? Thanks!!

Kaspersky is complaining on my systems


menu, settings, exceptions, ADD EXCEPTION highlighted in green.