MathCAD 15-050 Flexnet Licensing error 15,10. System error 10061 "winsock connection refused"

1. In accordance with "FLEXnet Licensing End User Guide" guide (PDF version of this guide can be found in attachment) error codes "FLEXnet licensing error: -15, 10" means the following:

-10: Feature has expired;
-15: Cannot connect to license server system. The server (lmgrd) has not been started yet, or the wrong port@host or license file is being used, or the TCP/IP port or host name in the license file has been changed.

Start with these steps: "Stop Server" --> "Start Server" --> "ReRead License File".

2. Try to contact with PTC's tech support by using "Mathcad Support Center": http://www.ptc.com/support/mathcad_supportCenter.htm