System.ArgumentNullException: Value cannot be null.

[zimoch84]

I want to use Your adapter, but unfortunately I have an error I cannot resolve. :

A message sent to adapter "WCF-Custom" on send port "xxx" with URI "loopback://localhost/" is suspended.
Error details: System.ArgumentNullException: Value cannot be null.
Parameter name: key
at System.ThrowHelper.ThrowArgumentNullException(ExceptionArgument argument)
at System.Collections.Generic.Dictionary2.Insert(TKey key, TValue value, Boolean add) at Microsoft.BizTalk.Adapter.Wcf.Runtime.WcfClient2.CreateChannelFactory[TChannel](IBaseMessage bizTalkMessage)
at Microsoft.BizTalk.Adapter.Wcf.Runtime.WcfClient2.InitializeValues(IBaseMessage message) at Microsoft.BizTalk.Adapter.Wcf.Runtime.WcfTransmitter2.GetClientFromCache(String spid, IBaseMessage message)
at Microsoft.BizTalk.Adapter.Wcf.Runtime.WcfAsyncBatch2.BatchWorker(List1 messages)
MessageId: {82C84194-1467-4A99-9724-03C06B64BA5D}
InstanceID: {7D93D5A4-11D9-4F30-82F0-3D386D59FD97}

Configuration is straightforward: One WCF-WebHttp Receive Location with passthrough pipelines and 1 Send port with Your adapter and Filter pointed to receive port

Any help would be appreciated