diff --git a/app/Http/Controllers/ClientPortalController.php b/app/Http/Controllers/ClientPortalController.php
index 0a768426d770..fe5f666c3e58 100644
--- a/app/Http/Controllers/ClientPortalController.php
+++ b/app/Http/Controllers/ClientPortalController.php
@@ -140,7 +140,7 @@ class ClientPortalController extends BaseController
         $paymentURL = '';
         if (count($paymentTypes) == 1) {
             $paymentURL = $paymentTypes[0]['url'];
-            if (in_array($paymentTypes[0]['gatewayTypeId'], [GATEWAY_TYPE_CUSTOM1, GATEWAY_TYPE_CUSTOM2, GATEWAY_TYPE_CUSTOM3])) {
+            if (array_key_exists('gatewayTypeId', $paymentTypes[0]) && in_array($paymentTypes[0]['gatewayTypeId'], [GATEWAY_TYPE_CUSTOM1, GATEWAY_TYPE_CUSTOM2, GATEWAY_TYPE_CUSTOM3])) {
                 // do nothing
             } elseif (! $account->isGatewayConfigured(GATEWAY_PAYPAL_EXPRESS)) {
                 $paymentURL = URL::to($paymentURL);
@@ -162,6 +162,11 @@ class ClientPortalController extends BaseController
             $showApprove = false;
         }
 
+        $gatewayTypeIdCast = false;
+
+        if(count($paymentTypes) >= 1 && array_key_exists('gatewayTypeId', $paymentTypes[0]))
+            $gatewayTypeIdCast = $paymentTypes[0]['gatewayTypeId'];
+
         $data += [
             'account' => $account,
             'showApprove' => $showApprove,
@@ -173,7 +178,7 @@ class ClientPortalController extends BaseController
             'paymentTypes' => $paymentTypes,
             'paymentURL' => $paymentURL,
             'phantomjs' => Request::has('phantomjs'),
-            'gatewayTypeId' => count($paymentTypes) == 1 ? $paymentTypes[0]['gatewayTypeId'] : false,
+            'gatewayTypeId' => count($paymentTypes) == 1 ? $gatewayTypeIdCast : false,
         ];
 
         if ($invoice->canBePaid()) {
diff --git a/app/Http/Controllers/InvoiceController.php b/app/Http/Controllers/InvoiceController.php
index 242f6009ac41..d21ae1c13fed 100644
--- a/app/Http/Controllers/InvoiceController.php
+++ b/app/Http/Controllers/InvoiceController.php
@@ -25,9 +25,9 @@ use App\Services\RecurringInvoiceService;
 use Auth;
 use Cache;
 use DB;
+use Illuminate\Support\Facades\Session;
 use Redirect;
 use Request;
-use Session;
 use URL;
 use Utils;
 use View;
@@ -427,7 +427,7 @@ class InvoiceController extends BaseController
             $response = $this->emailRecurringInvoice($invoice);
         } else {
             $userId = Auth::user()->id;
-            $this->dispatch(new SendInvoiceEmail($invoice, $userId, $reminder, $template));
+            dispatch(new SendInvoiceEmail($invoice, $userId, $reminder, $template));
             $response = true;
         }
 
diff --git a/app/Jobs/SendInvoiceEmail.php b/app/Jobs/SendInvoiceEmail.php
index effa021b9be7..efa5336773be 100644
--- a/app/Jobs/SendInvoiceEmail.php
+++ b/app/Jobs/SendInvoiceEmail.php
@@ -21,7 +21,7 @@ class SendInvoiceEmail extends Job implements ShouldQueue
     /**
      * @var Invoice
      */
-    protected $invoice;
+    public $invoice;
 
     /**
      * @var bool
diff --git a/app/Jobs/SendNotificationEmail.php b/app/Jobs/SendNotificationEmail.php
index cf475f77db4c..b6eec96adde1 100644
--- a/app/Jobs/SendNotificationEmail.php
+++ b/app/Jobs/SendNotificationEmail.php
@@ -2,51 +2,53 @@
 
 namespace App\Jobs;
 
+use App\Models\Invoice;
 use App\Models\Payment;
+use App\Models\Traits\SerialisesDeletedModels;
+use App\Models\User;
 use App\Ninja\Mailers\UserMailer;
 use Illuminate\Contracts\Queue\ShouldQueue;
 use Illuminate\Queue\InteractsWithQueue;
 use Illuminate\Queue\SerializesModels;
-use App\Models\Traits\SerialisesDeletedModels;
 
 /**
  * Class SendInvoiceEmail.
  */
 class SendNotificationEmail extends Job implements ShouldQueue
 {
-    use InteractsWithQueue, SerializesModels, SerialisesDeletedModels {
-        SerialisesDeletedModels::getRestoredPropertyValue insteadof SerializesModels;
-    }
+    use InteractsWithQueue;
+
+    public $deleteWhenMissingModels = true;
 
     /**
      * @var User
      */
-    protected $user;
+    public User $user;
 
     /**
      * @var Invoice
      */
-    protected $invoice;
+    public Invoice $invoice;
 
     /**
      * @var string
      */
-    protected $type;
+    public $type;
 
     /**
      * @var Payment
      */
-    protected $payment;
+    public ?Payment $payment;
 
     /**
      * @var string
      */
-    protected $notes;
+    public $notes;
 
     /**
      * @var string
      */
-    protected $server;
+    public $server;
 
     /**
      * Create a new job instance.
@@ -59,7 +61,7 @@ class SendNotificationEmail extends Job implements ShouldQueue
      * @param mixed         $type
      * @param mixed         $payment
      */
-    public function __construct($user, $invoice, $type, $payment, $notes)
+    public function __construct(User $user, Invoice $invoice, $type, ?Payment $payment, $notes)
     {
         $this->user = $user;
         $this->invoice = $invoice;
diff --git a/app/Listeners/NotificationListener.php b/app/Listeners/NotificationListener.php
index a906436519ec..b5d2af556410 100644
--- a/app/Listeners/NotificationListener.php
+++ b/app/Listeners/NotificationListener.php
@@ -1,17 +1,20 @@
-<?php namespace App\Listeners;
+<?php 
+
+namespace App\Listeners;
 
-use App\Ninja\Mailers\UserMailer;
-use App\Ninja\Mailers\ContactMailer;
-use App\Events\InvoiceWasEmailed;
-use App\Events\QuoteWasEmailed;
 use App\Events\InvoiceInvitationWasViewed;
-use App\Events\QuoteInvitationWasViewed;
-use App\Events\QuoteInvitationWasApproved;
+use App\Events\InvoiceWasEmailed;
 use App\Events\PaymentWasCreated;
-use App\Services\PushService;
+use App\Events\QuoteInvitationWasApproved;
+use App\Events\QuoteInvitationWasViewed;
+use App\Events\QuoteWasEmailed;
 use App\Jobs\SendNotificationEmail;
 use App\Jobs\SendPaymentEmail;
+use App\Models\Invoice;
+use App\Ninja\Mailers\ContactMailer;
+use App\Ninja\Mailers\UserMailer;
 use App\Notifications\PaymentCreated;
+use App\Services\PushService;
 
 /**
  * Class NotificationListener
@@ -49,7 +52,7 @@ class NotificationListener
      * @param $type
      * @param null $payment
      */
-    private function sendNotifications($invoice, $type, $payment = null, $notes = false)
+    private function sendNotifications(Invoice $invoice, $type, $payment = null, $notes = false)
     {
         foreach ($invoice->account->users as $user)
         {
diff --git a/app/Ninja/Mailers/UserMailer.php b/app/Ninja/Mailers/UserMailer.php
index 881ab1b1a90b..e47560246675 100644
--- a/app/Ninja/Mailers/UserMailer.php
+++ b/app/Ninja/Mailers/UserMailer.php
@@ -73,7 +73,7 @@ class UserMailer extends Mailer
         User $user,
         Invoice $invoice,
         $notificationType,
-        Payment $payment = null,
+        ?Payment $payment,
         $notes = false
     ) {
         if (! $user->shouldNotify($invoice)) {