Google authentication FreeRadius stop working

[Janet Wang]

Hello all,
I have google authentication Free Radius server. It is running Ubuntu. It is for 2 factor authentication for our Horzion View.  Since yesterday afternoon, this radius server stopped working.
It won't authenticator any domain users anymore.
I ran radtest from the box itself, it gave me err message:
radclient: no response from server for ID 88 socket 3

In the radius.log:

 Thu Dec  7 11:02:07 2017 : Error: Discarding duplicate request from client localhost port 50181 - ID: 222 due to unfinished request 0
Thu Dec  7 11:02:12 2017 : Error: Discarding duplicate request from client localhost port 50181 - ID: 222 due to unfinished request 0
Thu Dec  7 11:02:34 2017 : Error: WARNING: Unresponsive child for request 0, in component authenticate module pam
Thu Dec  7 11:02:35 2017 : Info: WARNING: Child is hung for request 0 in component authenticate module pam.
Thu Dec  7 11:02:37 2017 : Info: WARNING: Child is hung for request 0 in component authenticate module pam.
Thu Dec  7 11:02:39 2017 : Info: WARNING: Child is hung for request 0 in component authenticate module pam.
Thu Dec  7 11:02:42 2017 : Info: WARNING: Child is hung for request 0 in component authenticate module pam.

Would you please tell me how to solve the issues?
Thank you