diff --git a/SoObjects/Mailer/SOGoDraftObject.m b/SoObjects/Mailer/SOGoDraftObject.m
index 266de5dad..905efa103 100644
--- a/SoObjects/Mailer/SOGoDraftObject.m
+++ b/SoObjects/Mailer/SOGoDraftObject.m
@@ -2043,7 +2043,7 @@ static NSString    *userAgent      = nil;
 
       parser = [NGMailAddressParser mailAddressParserWithString: [self sender]];
       parsedSender = [parser parse];
-      emailAddress = [parsedSender address];
+      emailAddress = [[parsedSender address] lowercaseString];
 
       if (![emails containsObject: emailAddress])
         {