If you get an error like “ITS, New user session denied due to memory bottleneck” in you SAP systems SM21 logs and your WEB page comes with “Internal 500 error” then you should check your ITS Free Memory value like below…

If you get your SAP ITS WEB sites like this ;

And SM21 system logs shows the following messages ,

Then you should check your “ITS Available Memory” via transaction code SITSPMON

As you can see our SAP systems ITS available memory value is 0

Now the solution is very simple ;

If you don’t want to restart your SAP system then go to transaction code SM04 and kill the suspended  “Plugin HTTP” sessions  with “End Session” option.

Now let’s check the “ITS Memory Status” via transaction code SITSPMON again ,

As you can see from the below screen , now we have enough “Free Memory for ITS” to try it..

Let’s give a chance to web screen again after providing available memory for ITS ;

Thats it…