Ok,
If I remove the lines and replace it with that you suggest it's work fine.
But Why the same code work in the before release and in new release it crash?
For me is not possible that when I update the library I need to review the old code.
Do you agree?

Thanks,
Massimo

This below the code:

clientOPCUA = new EasyUAClient();

UAEndpointDescriptor uadesc = new UAEndpointDescriptor();
UACertificateAcceptancePolicy uacert = new UACertificateAcceptancePolicy();
uacert.AcceptAnyCertificate = true;
uadesc.CertificateAcceptancePolicy = uacert;
uadesc.UrlString = "opc.tcp://opcuaserver.com:48010";

UANodeElementCollection uaElColl = clientOPCUA.BrowseObjects(_devModel.UAEndpointDesc,UAObjectIds.Server);

As you can see I'm already going to set the CertificateAccetancePolicy.
where is the mistake?

When I try to browsing the dato from the OPC-UA Server whit the code below:
UANodeElementCollection uaElColl = clientOPCUA.BrowseObjects(_devModel.UAEndpointDesc,UAObjectIds.Server);

I received this exception:
Exception: OpcLabs.EasyOpc.UA.OperationModel.UAException: An OPC-UA operation failure with error ID 'System.NotSupportedException' occurred, originating from '' and with depth of 1. The inner exception, of type "System.NotSupportedException", contains details about the problem. ---> System.NotSupportedException: Setting an OPC UA certificate acceptance policy specific to an endpoint is not supported, as it cannot be reliably implemented due to limitations of the underlying UA stack. You can set the certificate acceptance policy globally.+ Connection attempt #1; last connected at 01/01/0001 00:00:00 (local); unconnected for 00:00:00.1090000.+ The client method called (or event/callback invoked) was 'BrowseMultiple[1]'. --- Fine della traccia dello stack dell'eccezione interna --- in OpcLabs.EasyOpc.UA.IEasyUAClientExtension.Browse(IEasyUAClient client, UABrowseArguments browseArguments) in OpcLabs.EasyOpc.UA.IEasyUAClientExtension.Browse(IEasyUAClient client, UAEndpointDescriptor endpointDescriptor, UANodeDescriptor nodeDescriptor, UABrowseParameters browseParameters) in OpcLabs.EasyOpc.UA.IEasyUAClientExtension.BrowseObjects(IEasyUAClient client, UAEndpointDescriptor endpointDescriptor, UANodeDescriptor nodeDescriptor) in Qualitas.DeviceAppOPC.DataAccess.OPCserverCH.Open() in C:\Progetti\AzureDevOps\FDI-FRAMEWORK\DeviceAppOPC\DataAccess\OPCserverCH.cs:riga 463(An OPC-UA operation failure with error ID 'System.NotSupportedException' occurred, originating from '' and with depth of 1. The inner exception, of type "System.NotSupportedException", contains details about the problem.) Trace: in OpcLabs.EasyOpc.UA.IEasyUAClientExtension.Browse(IEasyUAClient client, UABrowseArguments browseArguments) in OpcLabs.EasyOpc.UA.IEasyUAClientExtension.Browse(IEasyUAClient client, UAEndpointDescriptor endpointDescriptor, UANodeDescriptor nodeDescriptor, UABrowseParameters browseParameters) in OpcLabs.EasyOpc.UA.IEasyUAClientExtension.BrowseObjects(IEasyUAClient client, UAEndpointDescriptor endpointDescriptor, UANodeDescriptor nodeDescriptor) in Qualitas.DeviceAppOPC.DataAccess.OPCserverCH.Open() in C:\Progetti\AzureDevOps\FDI-FRAMEWORK\DeviceAppOPC\DataAccess\OPCserverCH.cs:riga 463;

Why?
Can you help me please?

Thanks,
Massimo Scattolaro