Unable to synchronize SharePoint library/Task with Outlook

Hello

Trying to synchronize SharePoint 2010 and Outlook gives me this error:

Task "SharePoint" reported error (0x80004005): "An error occurred either in this SharePoint task (Portail - Tasks Project).Retry to update folder.
If problem persists Contact the SharePoint site administrator. HTTP 500.
The server sends the following error message 'Microsofot.SharePoint.SoapServer.SoapServerException' was thrown

Need your help please
Thanks