Welcome to WebmasterWorld Guest from 188.8.131.52
I realize it could be a problem with the script I'm running, Uber uploader, a perl script that returns values to PHP, or perhaps my configuration. I've set timeouts pretty high along with max post sizes etc, to accommodate large file uploads. But I am at a loss as to why this only happens to a few people and only at random times.
Still many issues you look into there. You have the mail server sending out the email that may have a problem. The email recipient might have issues, or perhaps the email was regarded as spam and trashed. So many problems could go wrong here. How often does it happen? If it's only every once in awhile I wouldn't be too worried about it. If the other way around, you might want to spend more time tracking it down and fixing it. :)
The site owner relies on that email notification to start working on a users request. Without it, the user just assumes the owner is ignoring them.
It's completely random. Resending the same information from a failed attempt, always go thru (though I imagine if I sent it 1000 times, perhaps a few wouldn't).