Every time a client connects to our server, this error is being generated. I noticed a batch of them when the server was rebooted and every morning when the client computers boot up.
"The certificate received from the remote client application has not validated correctly. The error code is 0x80090325. the attached data contains the client certificate."
I checked the content as indicated and it appears to be the user certificate issued by the front-end server to each user sip address. The dates are valid on the certificates but when viewing the certificate on the PC client, it shows "Windows does not have enough information to verify this certificate".
We are not experiencing any problems with our clients, but would like to prevent our logs from getting filled up with this error. Since I haven't found any mention of this error in relation to Lync, I have to assume it isn't common.