Webdynpro application turns blanc/white after a some time passes

Hello,

If we open a webdynpro abap application standalone or via Portal ( no difference ) and leave it be for a while ( 10 a 20 minutes ). Afterwards we click on a button or trigger any action, the entire screen turns blanc. There is no error or time-out message, just a blanc screen.

Does anyone know if this is standard or if this is a parameter that we can change somewhere?

Thanks!

Kind regards,

Wouter