cannot establish Ikev2 connection programmatically

Hello. I am trying to setup Virtual Private Network (VPN) based on IKEV2 protocol which communicate with a Libreswan backend server. When I create .mobileconfig using AppleConfigurator2 all works fine.

I checked out the documentation and found that "On iOS for

NEVPNProtocolIPSec

NEVPNProtocolIKEv2

identityData

PKCS12 format.".

Here is my function to establish VPN Connection:

func setupVPNConnectio(withData pkcs12Data: Data)
    {
        let manager: NEVPNManager = NEVPNManager.shared()
        manager.loadFromPreferences(completionHandler: { error in
            if let e = error {
                print("error: " + e.localizedDescription)
                return
            }
            let protocolIKEv2 = NEVPNProtocolIKEv2()
            protocolIKEv2.authenticationMethod = .certificate
            protocolIKEv2.certificateType = .RSA
            protocolIKEv2.serverAddress = "serverAddress"
            protocolIKEv2.remoteIdentifier = "remoteId"
            protocolIKEv2.localIdentifier = "localId"
            protocolIKEv2.identityData = pkcs12Data
            protocolIKEv2.identityDataPassword = "password"
            protocolIKEv2.deadPeerDetectionRate = .medium
            protocolIKEv2.ikeSecurityAssociationParameters.encryptionAlgorithm = .algorithmAES128
            protocolIKEv2.ikeSecurityAssociationParameters.integrityAlgorithm = .SHA256
            protocolIKEv2.ikeSecurityAssociationParameters.diffieHellmanGroup = .group14
            protocolIKEv2.ikeSecurityAssociationParameters.lifetimeMinutes = 1440
            protocolIKEv2.childSecurityAssociationParameters.encryptionAlgorithm = .algorithmAES128
            protocolIKEv2.childSecurityAssociationParameters.integrityAlgorithm = .SHA256
            protocolIKEv2.childSecurityAssociationParameters.diffieHellmanGroup = .group14
            protocolIKEv2.childSecurityAssociationParameters.lifetimeMinutes = 1440
            manager.protocolConfiguration = protocolIKEv2
            manager.isEnabled = true
            manager.saveToPreferences(completionHandler: { error in
                guard error == nil else {
                    print("NEVPNManager.saveToPreferencesWithCompletionsHandler failed: \(error!.localizedDescription)")
                    return
                }
                do {
                    try manager.connection.startVPNTunnel(options: nil)
                } catch (let exception) {
                    print(exception)
                }
            })
        })
    }

But when I am trying to connect nothing is happened (without any errors). I connected VPN loging profile and AppleConfigurator2 to check logs. Here is output from console.

pfkey received SA is NULL

Certificate evaluation error =

kSecTrustResultRecoverableTrustFailure

Certificate is not trusted

Certificate authentication data could not be verified

Failed to process IKE Auth packet

When I trying to convert pkcs12 data to SecIdentity and evaluate SecTrust - nothing changed.

func evaluateIdentity(pkcs12Data: Data, password: String) throws
    {
        var importResult: CFArray? = nil

        let err = SecPKCS12Import(pkcs12Data as NSData, [kSecImportExportPassphrase as String: password] as NSDictionary, &importResult)

        guard err == errSecSuccess else {
            throw NSError(domain: NSOSStatusErrorDomain, code: Int(err), userInfo: nil)
        }

        let identityDictionaries = importResult as! [[String:Any]]
        let certificates = identityDictionaries[0] [kSecImportItemCertChain as String] as! [SecCertificate]
        let identity = identityDictionaries[0][kSecImportItemIdentity as String] as! SecIdentity
        let trust = identityDictionaries[0][kSecImportItemTrust as String] as! SecTrust
        var status = SecTrustSetAnchorCertificates(trust, certificates as CFArray )
        var resultType = SecTrustResultType.invalid
        print(status)

        status = SecTrustEvaluate(trust, &resultType)
        //Received status 4
    }

I also tried to save identiy to the keychain, but again - nothing changed.

func saveIdentity(identity: SecIdentity)  {

        var certificateRef: SecCertificate? = nil
        SecIdentityCopyCertificate(identity, &certificateRef)
        let subject = SecCertificateCopySubjectSummary(certificateRef!)


        let saveQuery = [
            kSecClass as String  : kSecClassIdentity,
            kSecValueRef as String : identity,
            kSecReturnRef as String : kCFBooleanTrue,
            kSecAttrAccessible as String : kSecAttrAccessibleAlways,
            kSecAttrLabel as String : subject!
            ] as [String : Any]

        var item: CFTypeRef? = nil

        var status = SecItemAdd(saveQuery as CFDictionary, &item)
        // Received status 0
    }

What I am doing wrong? And is it possible to establish this type of VPN connection programmatically?

Thanks.