diff --git a/native/cpp/CommonCpp/CryptoTools/CryptoModule.h b/native/cpp/CommonCpp/CryptoTools/CryptoModule.h
--- a/native/cpp/CommonCpp/CryptoTools/CryptoModule.h
+++ b/native/cpp/CommonCpp/CryptoTools/CryptoModule.h
@@ -71,7 +71,7 @@
   EncryptedData
   encrypt(const std::string &targetUserId, const std::string &content);
   std::string
-  decrypt(const std::string &targetUserId, EncryptedData encryptedData);
+  decrypt(const std::string &targetUserId, EncryptedData &encryptedData);
 
   std::string signMessage(const std::string &message);
   static void verifySignature(
diff --git a/native/cpp/CommonCpp/CryptoTools/CryptoModule.cpp b/native/cpp/CommonCpp/CryptoTools/CryptoModule.cpp
--- a/native/cpp/CommonCpp/CryptoTools/CryptoModule.cpp
+++ b/native/cpp/CommonCpp/CryptoTools/CryptoModule.cpp
@@ -340,19 +340,37 @@
 
 std::string CryptoModule::decrypt(
     const std::string &targetUserId,
-    EncryptedData encryptedData) {
+    EncryptedData &encryptedData) {
   if (!this->hasSessionFor(targetUserId)) {
     throw std::runtime_error{"error decrypt => uninitialized session"};
   }
   OlmSession *session = this->sessions.at(targetUserId)->getOlmSession();
 
-  OlmBuffer tmpEncryptedMessage(encryptedData.message);
+  OlmBuffer utilityBuffer(::olm_utility_size());
+  OlmUtility *olmUtility = ::olm_utility(utilityBuffer.data());
+
+  OlmBuffer messageHashBuffer(::olm_sha256_length(olmUtility));
+  ::olm_sha256(
+      olmUtility,
+      encryptedData.message.data(),
+      encryptedData.message.size(),
+      messageHashBuffer.data(),
+      messageHashBuffer.size());
 
+  OlmBuffer tmpEncryptedMessage(encryptedData.message);
   size_t maxSize = ::olm_decrypt_max_plaintext_length(
       session,
       encryptedData.messageType,
       tmpEncryptedMessage.data(),
       tmpEncryptedMessage.size());
+
+  if (maxSize == -1) {
+    throw std::runtime_error{
+        "error decrypt_max_plaintext_length => " +
+        std::string{::olm_session_last_error(session)} + ". Hash: " +
+        std::string{messageHashBuffer.begin(), messageHashBuffer.end()}};
+  }
+
   OlmBuffer decryptedMessage(maxSize);
   size_t decryptedSize = ::olm_decrypt(
       session,
@@ -363,7 +381,9 @@
       decryptedMessage.size());
   if (decryptedSize == -1) {
     throw std::runtime_error{
-        "error decrypt => " + std::string{::olm_session_last_error(session)}};
+        "error decrypt => " + std::string{::olm_session_last_error(session)} +
+        ". Hash: " +
+        std::string{messageHashBuffer.begin(), messageHashBuffer.end()}};
   }
   return std::string{(char *)decryptedMessage.data(), decryptedSize};
 }
diff --git a/native/cpp/CommonCpp/Notifications/BackgroundDataStorage/NotificationsCryptoModule.cpp b/native/cpp/CommonCpp/Notifications/BackgroundDataStorage/NotificationsCryptoModule.cpp
--- a/native/cpp/CommonCpp/Notifications/BackgroundDataStorage/NotificationsCryptoModule.cpp
+++ b/native/cpp/CommonCpp/Notifications/BackgroundDataStorage/NotificationsCryptoModule.cpp
@@ -274,9 +274,11 @@
     const std::string &callingProcessName) {
   std::string decryptedData;
   auto caller = [&](crypto::CryptoModule &cryptoModule) {
+    crypto::EncryptedData encryptedData{
+        std::vector<uint8_t>(data.begin(), data.end()), messageType};
     decryptedData = cryptoModule.decrypt(
         NotificationsCryptoModule::keyserverHostedNotificationsID,
-        {std::vector<uint8_t>(data.begin(), data.end()), messageType});
+        encryptedData);
   };
   NotificationsCryptoModule::callCryptoModule(caller, callingProcessName);
   return decryptedData;
diff --git a/native/ios/NotificationService/NotificationService.mm b/native/ios/NotificationService/NotificationService.mm
--- a/native/ios/NotificationService/NotificationService.mm
+++ b/native/ios/NotificationService/NotificationService.mm
@@ -60,18 +60,19 @@
   // Step 1: notification decryption.
   if ([self shouldBeDecrypted:content.userInfo]) {
     std::string decryptErrorMessage;
+    std::string notifID = std::string([content.userInfo[@"id"] UTF8String]);
     try {
       @try {
         [self decryptContentInPlace:content];
       } @catch (NSException *e) {
         decryptErrorMessage = "NSE: Received Obj-C exception: " +
             std::string([e.name UTF8String]) +
-            " during notification decryption.";
+            " during notification decryption. Notif ID: " + notifID;
       }
     } catch (const std::exception &e) {
       decryptErrorMessage =
           "NSE: Received C++ exception: " + std::string(e.what()) +
-          " during notification decryption.";
+          " during notification decryption. Notif ID: " + notifID;
     }
 
     if (decryptErrorMessage.size()) {