Mihai - thank you very much. This is a great offer
Personally, I think it has something to Do with my Hardware / Network Configuration. The only thing I did, was to change the license server from my workstation (3930K) to my Office PC (2550K), to have a Server running with less Power Consumption

. After that the subject begun. Sorry I didn't mention that before but I thought that it would make no difference on what machine the RLM Server is running. I completely uninstalled the License Server on the other PC and again there are no firewalls...
The weird thing is sometimes Studio works (licensed) and sometimes not MR is always working and recognizing the license.
My network configuration is the following:
Workstation, Office-PC, one Opteron MP are connected to an ASUS RT-N66U. The Router is connected to a GB-Switch in the cellar with the other Opteron MP nodes and the File Server running the Manager.
This configuration works without any problem with Network Rendering (
Monitor - Office PC with License Server -
Manager on the file server and all the nodes connected (Linux/WinX64/Mac OS X). As I said before Maxwell Render starts on every machine (is licensed) but Maxwell Studio sometimes starts and recognizes the license (server) without any problem and sometimes it doesn't connect doesn't find the License Server...
I will search on and I assume it is not a Maxwell/License related problem - it has something to do with my hardware...