openconnect client dtls handshake fail On Windows

[Guang]

Hi,
 I had used the openconnect (not the version 6.0.0  but the higher version  in git)(compiled on Fedora 20 in VMWare)
 And then DTLS handshake failed occurs. Just like below:

Microsoft (R) Windows Script Host Version 5.8
Copyright (C) Microsoft Corporation. All rights reserved.


VPN Gateway: 104.149.5.138
Internal Address: 10.1.1.209
Internal Netmask: 255.255.255.0
Internal Gateway: 10.1.1.1
Interface: "Local Area Connection 2"
Configuring "Local Area Connection 2" interface for Legacy IP...
done.
Configuring Legacy IP networks:
Route configuration done.
Connected Local Area Connection 2 as 10.1.1.209, using SSL
DTLS handshake failed: Resource temporarily unavailable, try again.

 And It will try a lot of times,but can't be successfull.

 but I dont't understand what  the " Resource temporarily unavailable" means. 

Thanks 
Guang