java.lang.NullPointerException: Attempt to invoke virtual method 'void java.io.FileDescriptor.setInt$(int) error in Facebook Audience SDK

I have integrated Facebook audience SDK

'com.facebook.android:audience-network-sdk:5.1.0'

in my project. Ad Showing properly in my device during debugging more but it crashing in the live version. Please note proguard is disable. A crash report is as per below.

java.lang.NullPointerException: Attempt to invoke virtual method 'void java.io.FileDescriptor.setInt$(int)' on a null object reference

java.lang.NullPointerException: Attempt to invoke virtual method 'void java.io.FileDescriptor.setInt$(int)' on a null object reference java.net.PlainSocketImpl.accept(PlainSocketImpl.java:98) java.net.ServerSocket.implAccept(ServerSocket.java:229) java.net.ServerSocket.accept(ServerSocket.java:147) com.facebook.ads.internal.v.b.f.a(Unknown Source) com.facebook.ads.internal.v.b.f$e.run(Unknown Source) java.lang.Thread.run(Thread.java:833)

I am getting this error in the Facebook Interstitial ad. How to resolve it?

from java.lang.NullPointerException: Attempt to invoke virtual method 'void java.io.FileDescriptor.setInt$(int) error in Facebook Audience SDK