In exchange 2003 (SBS server) you can specify serveral ways to limit the mails you want to send. ( I think)Because i've uncrossed the box in the properties of the smtp protocol: limit message size and also: limit session size ... But here is the thing: i still cann't send mail over 2 mb???

You can refer below article... How to Set Size Limits for Messages http://www.msexchange.org/tutorials/Set-Size-Limits-Messages.htmlAmit Tank | MVP Exchange Server | MCITP: EMA, MCSA: M | http://ExchangeShare.WordPress.com

Hello,Addition to Amit's post, you would like to check the following KB for understanding the message limit in exchange 2000 & 2003.Exchange 2000 Server and Exchange Server 2003 Message Restrictionshttp://technet.microsoft.com/en-us/library/aa996221(EXCHG.65).aspxArun Kumar | MCSE - 2K3 + Messaging | ITIL-F V3

Please check the size limits settings based on Amit and Aruns suggestions, if the issue still occurs after verified all size limits, please provide the following info for troubleshooting: 1. Issue scope: Single user or all users? 2. Whats the result if the mails cant be sent out? Does there have any NDR generated? If yes, please provide the error info and the message header in that NDR for analyzing 3. After reproduced the issue, is there any related warning or error info in the application log on the SBS server? Notes: For questions about the exchange on the SBS server please uses the SBS 2003 newsgroup which would be the best place for the question and have all experts on SBS server

Hi, thx for your response...1: All users2: result: Mails get sent out (very fast... ), but no report. Reveiver neverreceives the message or any report3: no log. Will try to monitor the message and find out what happend to it. This is a server from a client. Sadly enough I cannot check this server every day.

Yes, please monitor the issue Message Tracking Center and SMTP logging will help on such issue Troubleshooting Mail Flow and SMTP How to Enable Message Tracking Center on a Server