Logon Screen appears while executing a WDA from portal

Hi All,

I have done the following

1) created a WDA application in the ECC system

2) created a iview to run this WDA application on portal

3) included this iview in one of the ESS screen

When the user clicks on the link, a log on screen appears with two buttons "Logon" and "Delete password". It never allows me to logon, however if i click delete password it executes the WDA application and displays the screen. this seems to be a one time activity from the second time the user is allowed to execute the WDA no logon screen appears.

Can anyone help on why the logon screen is displayed?

Note: The logon screen appears only for few users for most users the WDA is executed without any problem.

Regards

Bharath Mohan B