I've got a InfoPath form with a reading data connection to a SOAP WebService that is secured by https and basic http authentication. The form is hosted in Forms Services an the data connection is configured in a udcx file in the site collection.
When I open the form in SharePoint and it tries to query the data connection, it fails and I get the following error in the SharePoint ULS log:
The root of the certificate chain is not a trusted root authority
I checked the certificates of the SharePoint machine account: The root certificate is in the trusted root authorities and the intermediate is also set right.
When I open the WebServices WSDL in an IE browser on the server, the certificate is accepted without problems.
Am I missing something? Do I have to trust this change at another place too? Maybe for the App Pool user or something?