Abnormaly connection closed

Hi , after of some period of time maybe 2-3 minutes our connection with server drops with this exception.

2/20/2016 9:58:51 PM|Fatal|<startReceiving>c__AnonStorey5.<>m__2|System.InvalidOperationException: Stream is closed.
                              at Mono.Net.Security.MobileAuthenticatedStream.CheckThrow (System.Boolean authSuccessCheck) [0x0000b] in /Users/builder/data/lanes/3969/44931ae8/source/xamarin-macios/_ios-build/Library/Frameworks/Xamarin.iOS.framework/Versions/git/src/mono/mcs/class/System/Mono.Net.Security/MobileAuthenticatedStream.cs:91 
                              at Mono.Net.Security.MobileAuthenticatedStream.ProcessReadOrWrite (Mono.Net.Security.AsyncProtocolRequest& nestedRequest, Mono.Net.Security.BufferOffsetSize2& internalBuffer, Mono.Net.Security.AsyncOperation operation, Mono.Net.Security.BufferOffsetSize userBuffer, System.Net.LazyAsyncResult lazyResult) [0x0006b] in /Users/builder/data/lanes/3969/44931ae8/source/xamarin-macios/_ios-build/Library/Frameworks/Xamarin.iOS.framework/Versions/git/src/mono/mcs/class/System/Mono.Net.Security/MobileAuthenticatedStream.cs:346 
                              at Mono.Net.Security.MobileAuthenticatedStream.BeginReadOrWrite (Mono.Net.Security.AsyncProtocolRequest& nestedRequest, Mono.Net.Security.BufferOffsetSize2& internalBuffer, Mono.Net.Security.AsyncOperation operation, Mono.Net.Security.BufferOffsetSize userBuffer, System.AsyncCallback asyncCallback, System.Object asyncState) [0x0000b] in /Users/builder/data/lanes/3969/44931ae8/source/xamarin-macios/_ios-build/Library/Frameworks/Xamarin.iOS.framework/Versions/git/src/mono/mcs/class/System/Mono.Net.Security/MobileAuthenticatedStream.cs:307 
                              at Mono.Net.Security.MobileAuthenticatedStream.BeginRead (System.Byte[] buffer, System.Int32 offset, System.Int32 count, System.AsyncCallback asyncCallback, System.Object asyncState) [0x00000] in /Users/builder/data/lanes/3969/44931ae8/source/xamarin-macios/_ios-build/Library/Frameworks/Xamarin.iOS.framework/Versions/git/src/mono/mcs/class/System/Mono.Net.Security/MobileAuthenticatedStream.cs:272 
                              at System.Net.Security.SslStream.BeginRead (System.Byte[] buffer, System.Int32 offset, System.Int32 count, System.AsyncCallback asyncCallback, System.Object asyncState) [0x00000] in /Users/builder/data/lanes/3969/44931ae8/source/xamarin-macios/_ios-build/Library/Frameworks/Xamarin.iOS.framework/Versions/git/src/mono/mcs/class/System/System.Net.Security/SslStream.cs:372 
                              at WebSocketSharp.Ext+<ReadBytesAsync>c__AnonStorey3.<>m__0 (System.IAsyncResult ar) [0x00031] in <7d8633e6c59e474f8b014bbb504c73b5>:0

Client is IOS application , everything works fine for just 2-3 minutes and then I need update my connection with server. Can you help me with some advise what I'm doing wrong.

Start with WebSocketSharp.Ext.ReadBytesAsync and the SslStream/MobileAuthenticatedStream frames in the reported stack trace. Reproduce the iOS client disconnect after 2–3 minutes, then determine where the stream is closed and verify the connection remains usable or fails with a clearly handled error.