diff --git a/src/core/abstract/MCErrorMessage.cpp b/src/core/abstract/MCErrorMessage.cpp
index bbe65eb12..2f3d2c983 100644
--- a/src/core/abstract/MCErrorMessage.cpp
+++ b/src/core/abstract/MCErrorMessage.cpp
@@ -46,6 +46,9 @@ static const char * localizedDescriptionTable[] = {
     "An application specific password is required",                                  /** MCOErrorGmailApplicationSpecificPasswordRequired */
     "An error when requesting date",                                                 /** MCOErrorServerDate */
     "No valid server found",                                                         /** MCOErrorNoValidServerFound */
+    "Error while running custom command",                                            /** MCOErrorCustomCommand */
+    "Cannot send message due to possible spam detected by server",                   /** MCOErrorSendMessageSpamSuspected */
+    "User is over the limit for messages allowed to be sent in a single day",        /** MCOErrorSendMessageDailyLimitExceeded */
 };
 
 String * mailcore::errorMessageWithErrorCode(ErrorCode errorCode)
diff --git a/src/core/abstract/MCMessageConstants.h b/src/core/abstract/MCMessageConstants.h
index 7d7403dac..d1029b138 100644
--- a/src/core/abstract/MCMessageConstants.h
+++ b/src/core/abstract/MCMessageConstants.h
@@ -253,6 +253,8 @@ namespace mailcore {
         ErrorServerDate,
         ErrorNoValidServerFound,
         ErrorCustomCommand,
+        ErrorYahooSendMessageSpamSuspected,
+        ErrorYahooSendMessageDailyLimitExceeded
     };
     
     enum PartType {
diff --git a/src/core/smtp/MCSMTPSession.cpp b/src/core/smtp/MCSMTPSession.cpp
index 10a6163b9..d0711c65e 100644
--- a/src/core/smtp/MCSMTPSession.cpp
+++ b/src/core/smtp/MCSMTPSession.cpp
@@ -694,6 +694,14 @@ void SMTPSession::sendMessage(Address * from, Array * recipients, Data * message
                 goto err;
             }
         }
+        else if (responseCode == 521 && response->locationOfString(MCSTR("over the limit")) != -1) {
+            * pError = ErrorYahooSendMessageDailyLimitExceeded;
+            goto err;
+        }
+        else if (responseCode == 554 && response->locationOfString(MCSTR("spam")) != -1) {
+            * pError = ErrorYahooSendMessageSpamSuspected;
+            goto err;
+        }
         
         * pError = ErrorSendMessage;
         MC_SAFE_REPLACE_COPY(String, mLastSMTPResponse, response);
diff --git a/src/objc/abstract/MCOConstants.h b/src/objc/abstract/MCOConstants.h
index 54648a0f3..419d8485a 100644
--- a/src/objc/abstract/MCOConstants.h
+++ b/src/objc/abstract/MCOConstants.h
@@ -413,6 +413,10 @@ typedef NS_ENUM(NSInteger, MCOErrorCode) {
     MCOErrorNoValidServerFound,
     /** Error while running custom command */
     MCOErrorCustomCommand,
+    /** Spam was suspected by server */
+    MCOErrorYahooSendMessageSpamSuspected,
+    /** Daily limit of sent messages was hit */
+    MCOErrorYahooSendMessageDailyLimitExceeded,
     /** The count of all errors */
     MCOErrorCodeCount,
 };