24.01.2022
08:52
Hi,
since 2 months I have problem with error which appears randomly - Failure sending mail. Unable to read data from the transport connection: net_io_connectionclosed. I use o365 smtp server smtp.office365.com to send e-mails from Webcon BPS.
Any idea what could be reason of this error?
24.01.2022
22:57
Hi Marek,
I didn't found much about this error. You probably also found this answer/suggestion.
https://stackoverflow.com/a/70338095
If you don't have multiple servers it probably won't apply to you.
Best regards,
Daniel
25.01.2022
15:49
Hi Marek,
I didn't found much about this error. You probably also found this answer/suggestion.
https://stackoverflow.com/a/70338095
If you don't have multiple servers it probably won't apply to you.
Best regards,
Daniel
Dear Marek, Daniel,
this may be an issue with TLS 1.2.. Try to enable or enforce TLS 1.2. when connecting to SMTP Office 365 (of not already done).
https://docs.microsoft.com/en-us/mem/configmgr/core/plan-design/security/enable-tls-1-2-client
I had problem where randomly some e-mails were not send from WEBCON BPS to O365 users via SMTP Office365. TLS 1.2 was the issue / solution. :)
Recently Microsoft stopped supporting TLS 1.0, TLS 1.1.
