Network Extension function startTunnelWithOptions is never triggered

the code of my app

    @interface VPNManager()
   
    @property (nonatomic, strong) VPNManagerModel *vpnConfigurationModel;
    @property (nonatomic, strong) NEVPNManager *manager;
    @property (nonatomic, assign) NSInteger writeAmount;
    @end


    @implementation VPNManager


  
    - (BOOL)startVPN {
  
        [[NSNotificationCenter defaultCenter] postNotificationName:@"showError" object:self userInfo:@{@"info": @"configManagerWithModel"}];
        if (self.vpnManager.connection.status == NEVPNStatusDisconnected) {
            NSError *error;
            [self.vpnManager.connection startVPNTunnelAndReturnError:&error];
           
            if (error != 0) {
                const char *errorInfo = [NSString stringWithFormat:@"%@",error].UTF8String;
          
                [[NSNotificationCenter defaultCenter] postNotificationName:@"showError" object:self userInfo:@{@"info": [NSString stringWithFormat:@"Start VPN Failed -%@",error]}];
            }else {
          
                //point A
                [[NSNotificationCenter defaultCenter] postNotificationName:@"showError" object:self userInfo:@{@"info": @"Start VPN Success !"}];
                return YES;
            }
        }else {
        
            [[NSNotificationCenter defaultCenter] postNotificationName:@"showError" object:self userInfo:@{@"info":[NSString stringWithFormat:@"Start VPN - The current connect status isn't NEVPNStatusDisconnected ! %ld",self.vpnManager.connection.status]    }];
        }
       
        return NO;
    }

and PacketTunnelProvider Network Extension

  #import "PacketTunnelProvider.h"

    
    #include 
    #include 
    #include 
   
    
    #define _NET_MTU                        1400
    #define _NET_REMOTEADDRESS              "10.10.10.1"
    #define _NET_SUBNETMASKS                "255.255.255.255"
    #define _NET_DNS                        "8.8.8.8"
    #define _LOCAL_ADDRESS                  "127.0.0.1"
    #define _NET_TUNNEL_IPADDRESS           "10.8.0.2"
   
    
    @interface PacketTunnelProvider ()
    @property NWTCPConnection *connection;
    @property (strong) void (^pendingStartCompletion)(NSError *);
    @end
   
    @implementation PacketTunnelProvider
   
    
    - (void)startTunnelWithOptions:(NSDictionary *)options completionHandler:(void (^)(NSError *))completionHandler{
       
        //point B
   
        [[NSNotificationCenter defaultCenter] postNotificationName:@"showError" object:nil userInfo:nil]; //send message to notify has been triggered
        NEPacketTunnelNetworkSettings *tunnelNetworkSettings = [[NEPacketTunnelNetworkSettings alloc] initWithTunnelRemoteAddress:@_NET_REMOTEADDRESS];
        tunnelNetworkSettings.MTU = [NSNumber numberWithInteger:_NET_MTU];
        tunnelNetworkSettings.IPv4Settings = [[NEIPv4Settings alloc] initWithAddresses:[NSArray arrayWithObjects:@_NET_TUNNEL_IPADDRESS, nil]  subnetMasks:[NSArray arrayWithObjects:@_NET_SUBNETMASKS, nil]];
        tunnelNetworkSettings.IPv4Settings.includedRoutes = @[[NEIPv4Route defaultRoute]];
        NEIPv4Route *excludeRoute = [[NEIPv4Route alloc] initWithDestinationAddress:@"10.12.23.90" subnetMask:@"255.255.255.255"];
        tunnelNetworkSettings.IPv4Settings.excludedRoutes = @[excludeRoute];
        [self setTunnelNetworkSettings:tunnelNetworkSettings completionHandler:^(NSError * _Nullable error) {
            if (error == nil) {
                log4cplus_info("VPNManager", "PacketTunnelManager - Start Tunel Success !");
                completionHandler(nil);
            }else {
                log4cplus_error("VPNManager", "PacketTunnelManager - Start Tunel Failed - %s !",error.debugDescription.UTF8String);
                completionHandler(error);
                return;
            }
        }];
        [self readPakcets];
    }

point A can be triggered, start VPN and show VPN icon on left top of iPhone correctly.

but point B never be triggered

your comment welcome