SSIS project error: unable to retrieve table information for connection manager

Hi All, 

In my practice, I want to take data from EXCEL to SQL Server.

1. I created a connection manager for MSSQLServer (by selecting the connection manager for the OLE DB connection)
2. Another connection manager for excel files
3. I added an Excel source to the data flow.
4. Now, when I try to edit the Excel source code so that I can view the data in the Excel file, this causes the following error.
"Could not to retrieve the table information for connection manager 'excel connection manager', failed to connect to the source using connection manager."

Thanks a lot!