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Article ID: 884 - Last Modified:

Maestro failed to start with the following error message. I have a license, so what can I do to fix this problem?

FATAL -15: Unable to obtain valid Maestro license key. MAESTRO_MAIN

This error occurs when the license server is not available. The steps below will help you to locate the source of the problem:

  1. Check whether you can connect to the license server machine: it may be down or you might have network problems.
  2. If you can connect to the license server machine, log on (as administrator or root) and check if the license server (lmgrd) is running. Restart it if it is not running—see Article 1899.
  3. If it is running, the ports used by the license server may be blocked, and you will have to open them. The license server uses ports in the range 27000-27009; the license file sets the default to 27008.

If the problem is still not fixed, submit a report request at, with information on the problem. See Article 281 for assistance on gathering the information.

Related Articles:

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#1899: How do I start or restart the license server?
#281: I have problems with access to the Schrödinger software licenses. Is there an easy way to collect all the system...
#518: Maestro fails to start and produces error messages. What can I do?

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