Empty graph results

I have two queries for my graph:

  • Application Insights

  • Azure Log Analytics:

     range timestamp from floor($__timeFrom(),1m) to floor($__timeTo(),1m) step 1m
     | join kind=leftouter
         | where cloud_RoleInstance startswith "web-"
         | summarize sum(itemCount) by bin(timestamp, 1m)
         | order by timestamp desc
     ) on timestamp
     | order by timestamp asc
     | project timestamp, errors = iff(isnotempty(sum_itemCount), sum_itemCount, 0)

When enabling one of the queries, each works and they show the proper label in the legend. When enabling both queries, the graph goes blank and the legend shows “Value Value”

Why can’t I show both series at the same time?