Error message when sending email mail shots based on a looping recordset

This has been an issue for a while. Initially the problem was that too many emails were being sent by the server, but that was resolved by adding limits to the number of emails sent.

And more recently I set it up so that when the site owner is sending these mailshots, a new window opens, and have added a progress bar, so that he has some visual feedback whilst emails are being sent, and can get back to the rest of the site in the original window.

And in testing, it all seems to work perfectly.

However, I still here from him sometimes to say its failed, with the error message:

Internal Server Error

The server encountered an internal error or misconfiguration and was unable to complete your request.
Please contact the server administrator, webmaster@searchtechuk.com and inform them of the time the error occurred, and anything you might have done that may have caused the error.
More information about this error may be available in the server error log.
Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.

I have been in touch with the hosting company who are not seeing any errors, for example relating to too many mails being sent.

The only thing showing on any error logs is the error:

Parameter 2 to Trigger_Default_FormValidation() expected to be a reference, value given in /home/searchte/public_html/includes/tng/tNG.class.php on line 228

Although I think that's a red herring as the log is littered with that error, suggesting its not related to the one above. Plus I don't think that tNG.class.php (an old ADDT file) is being referenced as part of the UE function.

The only other thing the hosting company could think of was that there might be a maximum execution time for the script.

If that is the case, can it be changed, or can it be set to send smaller batches, reset, and continue sending?

Although when it failed earlier today, it was sending 177 emails. The settings were to wait 14 seconds between emails, and send a max of 4 per minute, which doesn't seem like that large a recordset.

Any advice much appreciated.

That error is extremely vague and really only tells me that the server encountered a problem.

that problem could be anything.

It could be a bad email address in the list causing the SMTP Server to fail.

I have run into a similar issue with a couple hosting providers where an email address with a nonexistent domain would cause the page to time out and return a 503 error instead of just moving to the next one, though this would only happen some times.

It could be you are running into a similar issue.

without a more concrete error message though, it is hard to tell.

Thanks Jason - sorry its so vague, but that's all I have to go on, as there isn't anything else showing up in any logs on the server.

The non existent email address sounds like a good possibility though, as that would explain why it seems to be so random and only happen sometimes.

I guess that's a hard one to resolve. I've advised the site owner to check all the email addresses in his database are still valid.

The non existent email domain is the most likely cause.

using a double opt in system for registration helps prevent that.

Where users verify their email addresses at registration?

The site doesn't currently involve user registration. Its a small recruitment agency, so the owner has always just entered all the data manually. Plus I originally did the site back in 2006, so he's been tapping stuff in manually for about seven years. Plenty of scope for typos and dead email addresses.

Yeah, that points to the bad email addresses hypothesis as the most likely cause then.