just saw this error in the event log on pos :
Unable to communicate with server for upload. Please check username/password, server and database connections. Error Details: System.ServiceModel.CommunicationException: The maximum retry count has been exceeded with no response from the remote endpoint. The reliable session was faulted. This is often an indication that the remote endpoint is no longer available. ---> System.ServiceModel.CommunicationException: The maximum message size quota for incoming messages (1048576) has been exceeded. To increase the quota, use the MaxReceivedMessageSize property on the appropriate binding element. ---> System.ServiceModel.QuotaExceededException: The maximum message size quota for incoming messages (1048576) has been exceeded. To increase the quota, use the MaxReceivedMessageSize property on the appropriate binding element.
 --- End of inner exception stack trace ---
 at System.Runtime.AsyncResult.End[TAsyncResult](IAsyncResult result)
 at System.ServiceModel.Channels.ClientReliableChannelBinder`1.RequestAsyncResult.End(IAsyncResult result)
 at System.ServiceModel.Channels.ReliableBinderRequestAsyncResult.EndOperation(IAsyncResult result)
 at System.ServiceModel.Channels.ReliableOutputAsyncResult.OperationCallback(IAsyncResult result)
 --- End of inner exception stack trace ---

Server stack trace: 
 at System.ServiceModel.Channels.ReliableRequestSessionChannel.SyncRequest.WaitForReply(TimeSpan timeout)
 at System.ServiceModel.Channels.RequestChannel.Request(Message message, TimeSpan timeout)
 at System.ServiceModel.Channels.ServiceChannel.Call(String action, Boolean oneway, ProxyOperationRuntime operation, Object[] ins, Object[] outs, TimeSpan timeout)
 at System.ServiceModel.Channels.ServiceChannelProxy.InvokeService(IMethodCallMessage methodCall, ProxyOperationRuntime operation)
 at System.ServiceModel.Channels.ServiceChannelProxy.Invoke(IMessage message)

Exception rethrown at [0]: 
 at System.Runtime.Remoting.Proxies.RealProxy.HandleReturnMessage(IMessage reqMsg, IMessage retMsg)
 at System.Runtime.Remoting.Proxies.RealProxy.PrivateInvoke(MessageData& msgData, Int32 type)
 at Microsoft.Dynamics.Retail.SynchClient.Core.UploadServiceReference.IUploadService.GetUploadJobs(String dataStoreName)
 at Microsoft.Dynamics.Retail.SynchClient.Core.UploadAgent.Execute()System.ServiceModel.CommunicationException: The maximum retry count has been exceeded with no response from the remote endpoint. The reliable session was faulted. This is often an indication that the remote endpoint is no longer available. ---> System.ServiceModel.CommunicationException: The maximum message size quota for incoming messages (1048576) has been exceeded. To increase the quota, use the MaxReceivedMessageSize property on the appropriate binding element. ---> System.ServiceModel.QuotaExceededException: The maximum message size quota for incoming messages (1048576) has been exceeded. To increase the quota, use the MaxReceivedMessageSize property on the appropriate binding element.
 --- End of inner exception stack trace ---
 at System.Runtime.AsyncResult.End[TAsyncResult](IAsyncResult result)
 at System.ServiceModel.Channels.ClientReliableChannelBinder`1.RequestAsyncResult.End(IAsyncResult result)
 at System.ServiceModel.Channels.ReliableBinderRequestAsyncResult.EndOperation(IAsyncResult result)
 at System.ServiceModel.Channels.ReliableOutputAsyncResult.OperationCallback(IAsyncResult result)
 --- End of inner exception stack trace ---

Server stack trace: 
 at System.ServiceModel.Channels.ReliableRequestSessionChannel.SyncRequest.WaitForReply(TimeSpan timeout)
 at System.ServiceModel.Channels.RequestChannel.Request(Message message, TimeSpan timeout)
 at System.ServiceModel.Channels.ServiceChannel.Call(String action, Boolean oneway, ProxyOperationRuntime operation, Object[] ins, Object[] outs, TimeSpan timeout)
 at System.ServiceModel.Channels.ServiceChannelProxy.InvokeService(IMethodCallMessage methodCall, ProxyOperationRuntime operation)
 at System.ServiceModel.Channels.ServiceChannelProxy.Invoke(IMessage message)

Exception rethrown at [0]: 
 at System.Runtime.Remoting.Proxies.RealProxy.HandleReturnMessage(IMessage reqMsg, IMessage retMsg)
 at System.Runtime.Remoting.Proxies.RealProxy.PrivateInvoke(MessageData& msgData, Int32 type)
 at Microsoft.Dynamics.Retail.SynchClient.Core.UploadServiceReference.IUploadService.GetUploadJobs(String dataStoreName)
 at Microsoft.Dynamics.Retail.SynchClient.Core.UploadAgent.Execute()