Turn on session logging, and look in the log to see what is happening.

I'm using Pegasus 4.51 (June 23 2009) under Windows XP.  Everything was working fine until a few days ago.  Since then, messages without attachment that I send go through, but messages that do have attachments don't go through.  I have not changed any of my settings.  Any help?  Thanks.

1. Do you receive any error message back from your mail server? Possibly, your ISP sees the messages as spam, and blocks them. If so, you should get a warning message back, which appears as an e-mail in your inbox.

2. Can you see the e-mail with attachment in the Queue? (click Review queued mail... in the File menu)

The answer to both questions is "no."  No message with attachment goes through, and there is no trace of any of them.

The answer to both questions is "no."  No message with attachment goes through, and there is no trace of any of them.

Turn on session logging in Tools | Internet options | General to see what happens.

I did. Is there anything you suggest I should do once I reach Tools | Internet options | General?  To repeat:  everything seems to be working normally, except the sending of messages with an attachment doesn't go through; and there is no error message.