diff --git a/app/Http/Controllers/PostMarkController.php b/app/Http/Controllers/PostMarkController.php
index a6877b1e250c..81e618493c04 100644
--- a/app/Http/Controllers/PostMarkController.php
+++ b/app/Http/Controllers/PostMarkController.php
@@ -287,7 +287,6 @@ class PostMarkController extends BaseController
         $inboundEngine = new InboundMailEngine();
 
         if ($inboundEngine->isInvalidOrBlocked($input["From"], $input["To"])) {
-            Log::info('Failed: Sender is blocked: ' . $input["From"] . " Recipient: " . $input["To"]);
             return response()->json(['message' => 'Blocked.'], 403);
         }
 
diff --git a/app/Jobs/Brevo/ProcessBrevoInboundWebhook.php b/app/Jobs/Brevo/ProcessBrevoInboundWebhook.php
index 02901132fee1..864b0bdb9af8 100644
--- a/app/Jobs/Brevo/ProcessBrevoInboundWebhook.php
+++ b/app/Jobs/Brevo/ProcessBrevoInboundWebhook.php
@@ -31,7 +31,7 @@ class ProcessBrevoInboundWebhook implements ShouldQueue
 
     public $tries = 1;
 
-    private InboundMailEngine $engine = new InboundMailEngine();
+    private InboundMailEngine $engine;
 
     /**
      * Create a new job instance.
@@ -111,6 +111,7 @@ class ProcessBrevoInboundWebhook implements ShouldQueue
      */
     public function __construct(private array $input)
     {
+        $this->engine = new InboundMailEngine();
     }
 
     /**
@@ -128,8 +129,7 @@ class ProcessBrevoInboundWebhook implements ShouldQueue
 
             // Spam protection
             if ($this->engine->isInvalidOrBlocked($this->input["From"]["Address"], $recipient)) {
-                Log::info('Failed: Sender is blocked: ' . $this->input["From"]["Address"] . " Recipient: " . $recipient);
-                throw new \Error('Sender is blocked');
+                return;
             }
 
             // match company
diff --git a/app/Jobs/Mailgun/ProcessMailgunInboundWebhook.php b/app/Jobs/Mailgun/ProcessMailgunInboundWebhook.php
index 3ac892d8d081..1bf6caeb44dc 100644
--- a/app/Jobs/Mailgun/ProcessMailgunInboundWebhook.php
+++ b/app/Jobs/Mailgun/ProcessMailgunInboundWebhook.php
@@ -29,7 +29,7 @@ class ProcessMailgunInboundWebhook implements ShouldQueue
 
     public $tries = 1;
 
-    private InboundMailEngine $engine = new InboundMailEngine();
+    private InboundMailEngine $engine;
 
     /**
      * Create a new job instance.
@@ -37,6 +37,7 @@ class ProcessMailgunInboundWebhook implements ShouldQueue
      */
     public function __construct(private string $input)
     {
+        $this->engine = new InboundMailEngine();
     }
 
     /**
@@ -173,8 +174,7 @@ class ProcessMailgunInboundWebhook implements ShouldQueue
 
         // Spam protection
         if ($this->engine->isInvalidOrBlocked($from, $to)) {
-            Log::info('Failed: Sender is blocked: ' . $from . " Recipient: " . $to);
-            throw new \Error('Sender is blocked');
+            return;
         }
 
         // match company
diff --git a/app/Services/InboundMail/InboundMailEngine.php b/app/Services/InboundMail/InboundMailEngine.php
index f5deef5a874b..5880c9ee5bfa 100644
--- a/app/Services/InboundMail/InboundMailEngine.php
+++ b/app/Services/InboundMail/InboundMailEngine.php
@@ -39,6 +39,8 @@ class InboundMailEngine
     private ?bool $isUnknownRecipent = null;
     private array $globalBlacklistDomains = [];
     private array $globalBlacklistSenders = [];
+    private array $globalWhitelistDomains = []; // only for global validation, not for allowing to send something into the company, should be used to disabled blocking for mass-senders
+    private array $globalWhitelistSenders = []; // only for global validation, not for allowing to send something into the company, should be used to disabled blocking for mass-senders
     public function __construct()
     {
     }
@@ -70,15 +72,25 @@ class InboundMailEngine
             Log::info('E-Mail blocked, because from e-mail has the wrong format: ' . $from);
             return true;
         }
+        if (!filter_var($to, FILTER_VALIDATE_EMAIL)) {
+            Log::info('E-Mail blocked, because to e-mail has the wrong format: ' . $from);
+            return true;
+        }
 
         $parts = explode('@', $from);
         $domain = array_pop($parts);
 
         // global blacklist
+        if (in_array($from, $this->globalWhitelistDomains)) {
+            return false;
+        }
         if (in_array($domain, $this->globalBlacklistDomains)) {
             Log::info('E-Mail blocked, because the domain was found on globalBlocklistDomains: ' . $from);
             return true;
         }
+        if (in_array($domain, $this->globalWhitelistSenders)) {
+            return false;
+        }
         if (in_array($from, $this->globalBlacklistSenders)) {
             Log::info('E-Mail blocked, because the email was found on globalBlocklistEmails: ' . $from);
             return true;
@@ -89,7 +101,7 @@ class InboundMailEngine
         }
 
         // sender occured in more than 500 emails in the last 12 hours
-        $senderMailCountTotal = Cache::get('inboundMailSender:' . $from, 0);
+        $senderMailCountTotal = Cache::get('inboundMailCountSender:' . $from, 0);
         if ($senderMailCountTotal >= 5000) {
             Log::info('E-Mail blocked permanent, because the sender sended more than ' . $senderMailCountTotal . ' emails in the last 12 hours: ' . $from);
             $this->blockSender($from);
@@ -103,7 +115,7 @@ class InboundMailEngine
         }
 
         // sender sended more than 50 emails to the wrong mailbox in the last 6 hours
-        $senderMailCountUnknownRecipent = Cache::get('inboundMailSenderUnknownRecipent:' . $from, 0);
+        $senderMailCountUnknownRecipent = Cache::get('inboundMailCountSenderUnknownRecipent:' . $from, 0);
         if ($senderMailCountUnknownRecipent >= 50) {
             Log::info('E-Mail blocked, because the sender sended more than ' . $senderMailCountUnknownRecipent . ' emails to the wrong mailbox in the last 6 hours: ' . $from);
             $this->saveMeta($from, $to);
@@ -111,8 +123,8 @@ class InboundMailEngine
         }
 
         // wrong recipent occurs in more than 100 emails in the last 12 hours, so the processing is blocked
-        $mailCountUnknownRecipent = Cache::get('inboundMailUnknownRecipent:' . $to, 0); // @turbo124 maybe use many to save resources in case of spam with multiple to addresses each time
-        if ($mailCountUnknownRecipent >= 100) {
+        $mailCountUnknownRecipent = Cache::get('inboundMailCountUnknownRecipent:' . $to, 0); // @turbo124 maybe use many to save resources in case of spam with multiple to addresses each time
+        if ($mailCountUnknownRecipent >= 200) {
             Log::info('E-Mail blocked, because anyone sended more than ' . $mailCountUnknownRecipent . ' emails to the wrong mailbox in the last 12 hours. Current sender was blocked as well: ' . $from);
             $this->blockSender($from);
             $this->saveMeta($from, $to);
@@ -131,15 +143,15 @@ class InboundMailEngine
     public function saveMeta(string $from, string $to, bool $isUnknownRecipent = false)
     {
         // save cache
-        Cache::add('inboundMailSender:' . $from, 0, now()->addHours(12));
-        Cache::increment('inboundMailSender:' . $from);
+        Cache::add('inboundMailCountSender:' . $from, 0, now()->addHours(12));
+        Cache::increment('inboundMailCountSender:' . $from);
 
         if ($isUnknownRecipent) {
-            Cache::add('inboundMailSenderUnknownRecipent:' . $from, 0, now()->addHours(6));
-            Cache::increment('inboundMailSenderUnknownRecipent:' . $from); // we save the sender, to may block him
+            Cache::add('inboundMailCountSenderUnknownRecipent:' . $from, 0, now()->addHours(6));
+            Cache::increment('inboundMailCountSenderUnknownRecipent:' . $from); // we save the sender, to may block him
 
-            Cache::add('inboundMailUnknownRecipent:' . $to, 0, now()->addHours(12));
-            Cache::increment('inboundMailUnknownRecipent:' . $to); // we save the sender, to may block him
+            Cache::add('inboundMailCountUnknownRecipent:' . $to, 0, now()->addHours(12));
+            Cache::increment('inboundMailCountUnknownRecipent:' . $to); // we save the sender, to may block him
         }
     }