500 Internal Server Error - java.lang.NullPointerException

Dear Expert,

we have implemented the portal for giving access to external vendors that have to fulfill daily tasks in our system. Currently we have around 40 people potentially working daily in it.

We decided to reboot the system every night in order to avoid access problems as we experienced that after 2/3 working days some people could not acces it (500 internal server error) or noticed that the system was very slow.

It happened again today : we reboot Friday night, people worked Saturday and this morning two people called us saying they could not enter the portal because of 500 error and one noticed the system was very slow. We then rebbot the portal at lunchtime and in the afternnon all reported problems disappeared.

My question is : is it possible that we have to reboot the portal everyday in order to avoid this kind of problem (that seems to happen random and not for example always to the same users or because some users were doing something in particular...) ? It seems to me that our portal environment is a little bit weak or that we missed something during set up...

Any idea or suggestion ?

I thank you very much in advance for your help

Michela Tondi

SAP Manager tamoil Italia SpA