Number of VMs in "sticky" mode

What causes this issue?

"Sticky" mode means that a Java virtual machine has been permanently
assigned to a user context. If a VM has this operating mode, all
requests for the assigned user context can only be processed in this VM.
As a result, this VM, provided the associated Java session (and the user
context too) is not closed, is not available to other transactions and
users. (The ABAP analogon is the PRIV mode of work processes.)
A VM enters the "sticky" mode if within a client request the memory size
of the user context (Java session) exceeds the defined value
<DS:KENO.E43B6C44FA33B04DE10000000A42425B>Memory parameters</>).
You can control the behavior in the VMC system administration (SM53) by
setting the value in the view "Sitzungen".
You can find more information in the online documentation
<DS:KENO.001560AA0E081DEB91FD8250BEB8055A>VMC System Administration</>
(transaction SM53).

System Response

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.