System.Security.SecurityException: Microsoft Dynamics CRM has experienced an error.

Hi,

I have several plugins that run on the ootb incident entity.
This error appears randomly:

Unhandled Exception: System.ServiceModel.FaultException`1[[Microsoft.Xrm.Sdk.OrganizationServiceFault, Microsoft.Xrm.Sdk, Version=8.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35]]: System.Security.SecurityException: Microsoft Dynamics CRM has experienced an error. Reference number for administrators or support: #6D340D07Detail: 
<OrganizationServiceFault xmlns:i="www.w3.org/.../XMLSchema-instance" xmlns="schemas.microsoft.com/.../Contracts">
<ErrorCode>-2147220970</ErrorCode>
<ErrorDetails xmlns:d2p1="schemas.datacontract.org/.../System.Collections.Generic" />
<Message>System.Security.SecurityException: Microsoft Dynamics CRM has experienced an error. Reference number for administrators or support: #6D340D07</Message>
<Timestamp>2017-05-30T11:34:41.3266298Z</Timestamp>
<ExceptionRetriable>false</ExceptionRetriable>
<ExceptionSource>PluginExecution</ExceptionSource>
<InnerFault i:nil="true" />
<OriginalException>System.Security.SecurityException
at System.ComponentModel.Win32Exception.GetObjectData(SerializationInfo info, StreamingContext context)
at System.Runtime.Serialization.ObjectCloneHelper.GetObjectData(Object serObj, String&amp; typeName, String&amp; assemName, String[]&amp; fieldNames, Object[]&amp; fieldValues)


at Microsoft.Crm.Sandbox.SandboxAppDomainHelper.Execute(IOrganizationServiceFactory organizationServiceFactory, Dictionary`2 sandboxServices, String pluginTypeName, String pluginConfiguration, String pluginSecureConfig, IPluginExecutionContext requestContext, Boolean enablePluginStackTrace, Boolean chaosFailAppDomain)
at Microsoft.Crm.Sandbox.SandboxWorker.Execute(SandboxCallInfo callInfo, SandboxPluginExecutionContext requestContext, Guid pluginAssemblyId, Int32 sourceHash, String assemblyName, Guid pluginTypeId, String pluginTypeName, String pluginConfiguration, String pluginSecureConfig, SandboxRequestCounter&amp; workerCounter, Boolean returnTraceInfo)</OriginalException>
<TraceText i:nil="true" />
</OrganizationServiceFault>

Server stack trace: 
at System.ServiceModel.Channels.ServiceChannel.HandleReply(ProxyOperationRuntime operation, ProxyRpc& rpc)
at System.ServiceModel.Channels.ServiceChannel.Call(String action, Boolean oneway, ProxyOperationRuntime operation, Object[] ins, Object[] outs, TimeSpan timeout)
at System.ServiceModel.Channels.ServiceChannel.Call(String action, Boolean oneway, ProxyOperationRuntime operation, Object[] ins, Object[] outs)
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.Crm.Sandbox.ISandboxHost.ExecuteAndReturnTraceInfo(SandboxCallInfo callInfo, SandboxPluginExecutionContext requestContext, Guid pluginAssemblyId, Int32 sourceHash, String assemblyName, Guid pluginTypeId, String pluginTypeName, String pluginConfiguration, String pluginSecureConfig, String assemblyContents, Boolean returnTraceInfo)
at Microsoft.Crm.Sandbox.SandboxPlugin.Execute(SandboxClient client, SandboxCallTracker callTracker, IExecutionContext requestContext, String assemblyContents, Boolean returnTraceInfo)
at Microsoft.Crm.Sandbox.SandboxCodeUnit.Execute(IExecutionContext context)

If I immediately close the error window and try again everything works correctly.

Any idea why it fails from time to time?

Thanks!