Error: -15 Cannot connect to license server


Typically, this error has to do with a problem within the operating system. Often this error comes along with a general error.


One common problem is that the firewall may be blocking the port used by the thinkbox vendor daemon, which means the client application cannot connect. While lmgrd itself will by default listen on IPv6 at port 27000, the vendor daemon itself will choose a port at random if not configured.

Another cause of this error can be if the license file is using a host name instead of an IP address on the “SERVER” line to refer to the license server, it’s possible that the lmgrd is unable to connect to the vendor daemon.



Solution: Verify that the firewall is the cause, by temporarily disabling it if it is safe to do so. If disabling the firewall allows licenses to be checked out, you will need to allow the thinkbox vendor daemon to pass through.

It should be possible on OS X and Windows to either create program-based exceptions to the firewall, or allow custom ports. The first option you will be allowing any ports destined for thinkbox, regardless of number. Otherwise, you need to assign a static port for the vendor daemon in the license file and also open the same port number on the firewall. For Linux you will need to set and allow the custom port number.

Refer to our page on disabling or configuring your firewall for instructions on this. As well, for more information on setting a specific vendor daemon port see Setting License Server Ports.

The hostname may not be resolvable

A simple test would be to try to run the command ‘ping hostname‘ where hostname is the name found on the “SERVER” line within the license file. If no answer returns, this is likely the problem. To stop the ‘ping’ command on Linux and OS X, hold the control (‘ctrl’) key, and press the ‘c’ key.

Solution: If the ping was unsuccessful and you know the IP address of the license server, you may use that in the license file in place of the host name.