Portal logout not working in IE

Hello All,

From past few weeks, I am facing an issue in our CE7.3 EHP1 SPS8 Portal's custom header/AFP, that when user clicks on 'Logout', screen refreshes and again loads portal with same user. No logout takes place.

It works OK in Chrome & Firefox.

Any ideas/pointers what must be going wrong here?

Thanks & Regards,

Amey