Cannot fetch dataSource due to Unknown exception

[noppanit]

I've just upgraded Druid to 0.9.1 and it broke my Pivot. I tried upgrading Pivot to 0.9.36 which is the latest release but I get this error

[root@- pivot]# pivot --druid druid-broker.conde.io:8082
Will refresh data sources every 10000ms
Listening on 9090
Adding Druid data source: 'sparrow-firehose-web'
Adding Druid data source: 'twitter-firehose-web'
Failed to introspect data source: 'twitter-firehose-web' because Unknown exception
Failed to introspect data source: 'sparrow-firehose-web' because Unknown exception
Initial introspection complete. Got 2 data sources, 0 queryable
Failed to introspect data source: 'twitter-firehose-web' because Unknown exception
Failed to introspect data source: 'twitter-firehose-web' because Unknown exception
Failed to introspect data source: 'sparrow-firehose-web' because Unknown exception
Failed to introspect data source: 'sparrow-firehose-web' because Unknown exception

I also tried it with config.yaml but it wasn't working either.

port: 9090
clusters:
  - name: druid
    type: druid
    host: ip-address:8082
    version: 0.9.1-legacy-lookups
    sourceListScan: auto
    sourceListRefreshOnLoad: true
    timeout: 60000

dataSources:

  - name: sparrow-firehose-web
    source: sparrow-firehose-web
    title: Web Firehose
    engine: druid

    defaultDuration: P1D

    defaultPinnedDimensions: ["cKe"]
    introspection: autofill-dimensions-only

    measures:
      - name: count
        title: Events
        expression: $main.count()