Hi Anurag,
Yes I am calling a transaction from Portal and trying to save / download the excel from there. The behaviour is quite normal if I perform the same from GUI, the file gets downloaded without any issue.
I have tried all other options, with different PC,different user IDs but no luck.
Also to add there has not been any major activity either on Portal side or on the R/3 side.
This is a bit weird as nothing has changed at system level or at the server level.
Sunny