emma,
While we are scratching our heads over this, I have a thought.
Let’s create an SMTP log file that we can examine when the problem exists.
Follow these instructions. It’s really simple.
To create an Smtp.log file, use the following steps:
Start Outlook Express.
On the Tools menu, click Options.
On the Advanced tab, under Logging Options, click the Mail Transport check box to select it.
Click Apply, and then click OK.
For Windows 98, the Smtp.log file is created and stored in the Windows\Application Data\Microsoft\Outlook Express\Mail folder
Once the problem has manifested itself again, post the logfile here so it can be examined.
Techie