title: Azure data factory copy activity fails. Login failed for user
body: <p>We are trying to copy data from on prem SQL server to azure blob storage through data factory copy activity. </p>
  
  <ol>
  <li>Installed data management gateway and connect.</li>
  <li>build copy pipeline to copy a table to azure blob, which ran fine for a week</li>
  </ol>
  
  <p>We are recently seeing this error since 2 days now</p>
  
  <blockquote>
    <p>Copy activity encountered a user error at Source side: ErrorCode=UserErrorFailedToConnectToSqlServer,'Type=Microsoft.DataTransfer.Common.Shared.HybridDeliveryException,Message=Cannot connect to SQL Server: '', Database: '', User: ''.,Source=Microsoft.DataTransfer.ClientLibrary,''Type=System.Data.SqlClient.SqlException,Message=Login failed for user 'chinese char displayed here'.,Source=.Net SqlClient Data Provider,SqlErrorNumber=18456,Class=14,ErrorCode=-2146232060,State=1,Errors=[{Class=14,Number=18456,State=1,Message=Login failed for user 'chinese char displayed here'.,},],'.</p>
  </blockquote>
  
  <p>Client is able to login into sql server with same credentials given in data management gateway. checked the status of management gateway and it is fine and even ran a diagnostic check of connection from management gateway</p>