EKU Client certicate expired

Question

Hi everyone,

We have a strange issue in our environment. Since some weeks clients receive a pop-up with a warning that the EKU certificate is expired.
It is not possible to save any details from the certificate to file, neither was I able to find the certificate in the personal or in the local machine certificate store.

we don't use Skype and have MS Teams in place, without SIP calling.

anyone had a similar issue before and was able to solve it?
any help is appreciated.
thanks
SV