BW Netweaver connection not showing data

Hello EveryOne,

Have already searched forum before posting , but did not get any relevant solution.

I have a requirement of using BW netweaver connection in dashboard , My problem is BEx query is showing data in  analyzer , but when i am launching it in dashboard , no data is coming for the query. Query is externally allowed.

Launching the dashboard getting error message:

The data connection session with BI Web runtime over the BICS Remote Web Service is expired. Press F5 to refresh the dashboard.

Please guide for the same....

Thanks in advance,

Vaishali Wadhwa.