Update data-flow-troubleshoot-guide.md

Author: kromerm

articles/data-factory/data-flow-troubleshoot-guide.md

@@ -7,7 +7,7 @@ author: kromerm
 manager: anandsub
 ms.service: data-factory
 ms.topic: troubleshooting
-ms.date: 02/04/2020
+ms.date: 04/02/2020
 ---
 # Troubleshoot data flows in Azure Data Factory
 
@@ -50,6 +50,18 @@ This article explores common troubleshooting methods for data flows in Azure Dat
 - **Causes**: No column name was specified
 - **Recommendation**: Set an alias if using a SQL function such as min()/max(), etc.
 
+### Error code: GetCommand OutputAsync failed
+
+- **Message**: During Data Flow debug and data preview: GetCommand OutputAsync failed with ...
+- **Causes**: This is a back-end service error. You can retry the operation and also restart your debug session.
+- **Recommendation**: If retry and restart do not resolve the issue, contact customer support.
+
+### Error code: Hit unexpected exception and execution failed
+
+- **Message**: During Data Flow activity execution: Hit unexpected exception and execution failed.
+- **Causes**: This is a back-end service error. You can retry the operation and also restart your debug session.
+- **Recommendation**: If retry and restart do not resolve the issue, contact customer support.
+
 ## General troubleshooting guidance
 
 1. Check the status of your dataset connections. In each Source and Sink transformation, visit the Linked Service for each dataset that you are using and test connections.