Hello, A few days ago I've posted an SMTP related question about timeouts. (SMTPClient sending). I was able the repeat the situation on Linux as well with Postfix SMTP server on the other side (The original question was Windows / Exchange Server) Now smtp works and there are two consequences, at least for Pharo/Seaside beginners like I am :) - Using Halt for debugging in such a Seaside project when sending SMTPClient emails could make this timeout. It waits for signal not coming and it maybe related to timeout handling inside what I don't understand. If you face SMTPClient timeout in the DATA phase of sending an email check if you are debugging (in debugger window, using halts, etc) and try without that (eg. Transcript show: logs or something else to check what is going on). - Pay extra attention to email mime type and content encoding including subject string of the message. Since I'm sending hungarian language emails it was essential. Server answers and sensitivity on exotic email messages depends on the SMTP server implementation in question, but staying minimal on smtp fields is always a good idea. Specify To: and From: fields in the DATA part also. When I created correct email DATA part with correct encoding and removed debugging from the Seaside application code (so debugger was not active when run into SMTP sending) emails started to go out with no problem. good night R