session timeout

hello,

we run SAP ME version6.0.4.31. I need to modify the Session Timeout and increase it to 300 min by going to:Netweaver Administrator -> Configuration Management -> Infrastructure -> Application Modules and find Web Module called "manufacturing", and below, in Web Module Details --> Context tab. I changed the Session Timeout parameter to 300 min and saved the change. but the problem is the session timout parameter was not changed after saving. I don't know what's the reason for this issue? why the change is not saved?

thank you

Regards,

Vian