Checkbox Force user to change password is checked, still it does not show password prompt

Hi AllCheckbox Force user to change password is checked, still it does not show password prompt, when mailfile of user is accessed through web browser.

I have done following settings -

In person doc - select user

Set password field > Check Password.

Force user to change password on next login - mark this checkbox

In Server doc

Check passwords on Notes IDs : enabled

Session authentication: Single Server

Can anybody please help.

regards

Kepatil