In the past week one of my clients using a VFP app which sends e-mails via WW Internet & Client Tools has started to experience intermittent Failure sending mail Error Messages. Sometimes E-Mails will go out numerous times successfully, followed by a series of Failure sending mail Error Messages followed by hit or miss successful sends.
The SMTP Server is: smtp.office365.com:587
Most likely hitting quota limits with office365. Depending on your plan you likely have a limited number of messages you can send per hour (or whatever).
If you're doing bulk mailing, using a generic provider like Office365 or GMail really is not an option.
+++ Rick ---
Thanks for your reply Rick
Not sending bulk mail How do I determine quota parameters?
Not sure. Look in the Office 365 service agreements.
There's probably also some way to look at the logs to see what goes wrong. Also check the full error message you get back from the send message...
Given intermittent behavior I would fully expect the SMTP server refusing to send messages - if it works once - unless you're passing invalid information on certain requests - it should always work from the client perspective.
+++ Rick ---
Normally I would get an SMPT Error Message with a number. In this case all I'm seeing is Failure sending email with no number.
That sounds like a connection error, server refusing the connection. The error info comes from .NET and wwSmtp just forwards what's available.
Make sure you're using a recent version as there has been an update that provides more error information in the latest update (7.23). It may provide more detail than that Failure to send error.
+++ Rick ---
OK - will recompile my test program with version 7.23 and see if more detail is available.
Marshal
It appears that something has changed with Office365 smtp email. We have a number of clients that are using the smtp server: smtp.office365.com:587. We are getting more and more reports of intermittent failures 'Failure sending email'. It seems that the intermittency is becoming more failures than successes. Is anyone aware of what may be the root of the issue? Or a fix? T
I recompiled my VFP App with Version 7.23 (Previously was running 6.15) and issue seems to have gone away for now - will be monitoring the situation.
Is it possible one of the bug fixes in 7.23 or previous 7.xx Versions could have also fixed this issue?
Also: Did Version 7.23 or previous 7.xx Versions automatically use TLS 1.2?
Hi Tom,
The jury is still out but re-compiling my VFP App with Version 7.23 seems to have fixed the issue. Waiting to hear back from Rick (see the previous Post).
Marshal
v7 uses TLS 1.2 by default. Older versions were using the defaults which would have been OS specific with Windows 10 getting TLS automatically, anything else only if the OS had enabled explicit TLS 1.2 support. I don't think that was your problem though because that's all or nothing. It either works or it doesn't.
The tools are updated regularly so it's possible some minor change helped with your issue, but I doubt it - the intermittent behavior seems to suggest it had to do with the O365 server limits. You'll find if or when you get another error and can look at the error message.
+++ Rick ---