Shibboleth 3: Service 'shibboleth.AttributeResolverService': Initial load failed

[Rod Widdowson]

>          <dc:ReturnAttributes>uid</dc:ReturnAttributes>
>          <ConnectionPool minPoolSize="3"/>
>      </resolver:DataConnector>

You'll almost certainly need to wait for Daniel to explain what is going on
but from my reading of the code you might make this go away by saying

          <ConnectionPool minPoolSize="3" validatePeriodically="true"/>

HTH

Rod