Faxing from Faxmail.com not working with more than 250KB file

Question

We have used Faxmail.com to send fax (Email to fax) from one of our ASP.NET application, and it has been working from ages, suddenly its failing to send fax if the file size is more than 250 KB. We have been sending fax with file size up to 8 MB with same application before.

Eg :-18180000000@faxmail.com

Send the email message from SMTP to the desired fax user and it used to deliver to fax machine.

SmtpClient smtp = new SmtpClient();
MailMessage nm = new MailMessage();
smtp.Host = "smtp.domain.com";
smtp.Send(nm);

We don't see any exceptions while sending email, however its not reaching fax machine (receipient).

Note :- This was been working since early 2000.

Answer 1

We found the issue was at the easylink server which is the service provider for faxmail.com. Easylink was failing to render the PDF attachment that was being sent. Upgrading the server with latest PDF patch resolved the issue.

Answer 2

You might want to start by checking your mail server logs. These should show whether or not the message was delivered to faxmail's mail server - and if so, you should see a receipt acknowledgement from faxmail's mail server. If the record shows successful delivery, then you can forward the record to faxmail, and they should be able to troubleshoot to find the reason that the message wasn't processed by their system. If the mail server logs show an error delivering the message, there should be a description that you can go on to troubleshoot. If you don't find a record at all, then it means the problem is on your end - the message is getting dropped somewhere before it is sent.