The certificate received from the remote server was issued by an untrusted certificate authority. Because of this, none of the data contained in the certificate can be validated. The SSL connection request has failed. The attached data contains the server certificate.
You are getting this error because a certificate that was issued can't be validated. Unfortunately, the error message itself doesn't tell you who issued the non-trusted certificate.
In order to find this out you will have to look at the binary data. The easiest way to do that is to use the built-in event viewer of EventSentry (or EventSentry Light which is free), which includes a text-view of binary data through the "text (filtered)" tab in the event details.
You can also copy/paste the binary data into a hex editor, you should then be able to see the text part of the certificate that will show you more details, such as which server issued the certificate etc.