Rhino node suddenly NOT able to find ZOO server

I have an issue with a couple of Rhino installations (on Window 7 & 8) where, for no apparent reason, they stop being able to find the ZOO license server.

The ZOO server IS running as other Rhino´s on the network are using it.

I´m pretty sure that nothing has been changed on the machine between when it works and stops working.

The ZOO Diagnostic tools has no problem finding ZOO!

I tried to disable IPV6 as this sometimes helps other licensing issues - no help.

The ONLY way I can get it to work is by un-installing and re-installing Rhino 5 (from a fresh download). And then it finds the ZOO Server immediately?

McNeel has not seen this before support tells me - has anybody else? and did you find a more elegant way around it.

(hmm just writing this I get unsure if the Rhino´s in question, was updated to the latest service pack. That could be a reason, that a fresh download works as they usually are the latest builds, I think)


Very strange.
To be clear, when a workstation has a problem getting a license, have you run the Zoo diagnostic tool on that machine right then before doing anything else?
I suspect some other utility (like Skype), has been loaded, and is monitoring port:80.

Another thing to check is the Zoo log file to see if it is “hearing” the request for a license and granting one.

A Client of mine has experienced the same thing, they have sent me this screen grab of the dialogue box. Any advice regarding how to proceed?

Download and run the Zoo Diagnostic Utility from the Workstation, and run the 5 tests.
The two most likely are installing Skype and forgetting to turn off it’s Port:80 monitoring, or using a TCP/IP address instead of the server Domain name, when assigning IP addresses by DHCP.

THere are other possibilities.
Here’s the link to the tool: