Qt OPC UA: Problems with Waterpump Example

[Mauda]

Dear Community,

my operating system is:

• Xubuntu 20.04

• Qt Creator 4.13.3

• Qt Version 5.15.2

Currenty I am trying to implement my own Client/Server Example by using the official Waterpump Example as source.
My example runs in a stable way, but I still have a problem with the handing over of an enum.
During the execution (release build) of my project, I get the following error code:

qt.opcua.plugins.open62541: Could not call method: BadNodeClassInvalid

I am not shure, how to fix this problem. I checked all NodeIDs on server and client side, but nothing helped.
Is there anyone, who had the same problem? How can I solve this?

If you need more code, please let me know.

Thank you in Advance!