Using:

loSmtp=CREATEOBJECT("wwSmtp")

When calling:

llResult = loSmtp.SendMail()  

I am intermittently getting an error: Unable to read data from the transport connection. net_io_connectionclosed

I need some guidance as to what the problem might be please.

Jill Lindgren

Firewall may be an issue or Anti-Virus interfering with your connection. AV more likely if it's intermittent. Make sure that there are no blocks on your SMTP port - start with adding the application or the port to the allowed list in Windows Firewall.

+++ Rick ---

What version of West Wind Client Tools are you using? I've been getting this error since early October when using SSL and smtp.office365.com. In the last couple of weeks it has been nearly 50% of emails. Upgraded to v7.23 today and, fingers crossed, all looking good so far.

Michael

Thank you Michael. I will look into upgrading my tools. I think we are using 6.0.

I don't think anything has changed in recent versions of wwSmtp, unless you were using a fairly old version. Sometime around the late sixes the code was changed to explicitly enable TLS 1.2 in the .NET library which would default that protocol but that was a some time ago now...

I think if you're getting intermittent failures the failures have to do with the service, not the library. It either works or it doesn't unless Office 365 uses different servers with different server software on it.

Quotas perhaps?

+++ Rick ---

I've upgraded from v5.51. The upgrade is definely the reason I've stopped getting net_io_connectionclosed errors.

Michael

Yeah that makes sense - those versions probably did not have the TLS 1.2 settings auto-enabled.

+++ Rick ---