An error occurred while attempting to establish an SSL or TLS connection.

[arshanskiyav]

Dobar dan

I have server with Windows Server 2022 (on based of Windows 11). I install Cobian Reflector version 2.3.x. I set up a mail connection with secure using the mail provider guide. But when i checked connection i get error:

An error occurred while attempting to establish an SSL or TLS connection.

This usually means that the SSL certificate presented by the server is not trusted by the system for one or more of
the following reasons:

1. The server is using a self-signed certificate which cannot be verified.
2. The local system is missing a Root or Intermediate certificate needed to verify the server's certificate.
3. A Certificate Authority CRL server for one or more of the certificates in the chain is temporarily unavailable.
4. The certificate presented by the server is expired or invalid.
5. The set of SSL/TLS protocols supported by the client and server do not match.
6. You are trying to connect to a port which does not support SSL/TLS.

See https://github.com/jstedfast/MailKit/bl ... eException for possible solutions.

I updated cobiant to the latest version 2.3.12, error persisted
Then I installed older version - 1.1.5, it doesn't help.

I'm using an app password (viewtopic.php?f=4&t=1109).

I checked with another mail provider (GMAIL) and I get the same error

Then I decided to try to check with a proxy server of another country and i get same error

Then I decided to try checking the mail connection in Cobian Backup (Gravity) and the connection was successful.

I have installed the latest windows updates, but am also getting this error

Thanks for your attention.
Andrey Arshanskiy

[cobian]

What kind of server (provider) is that?

[arshanskiyav]

Hi, thanks for your attention.
I use Yandex (smtp.yandex.ru/smtp.yandex.com/smtp.yandex.net) and Google (smtp.gmail.com) SMTP servers. Problem persisted on all servers.
The latest version of Reflector on an older OS successfully connects to these smtp servers.

[cobian]

This may be due to newer OSs having a policy to block older encryption methods. I'll take a look at that and see if I can find some solution.

[arshanskiyav]

But sending mail works in Cobian Backup

[cobian]

Will check this out

[katyswift468]

When I send batch mail, an error prompted “An error occurred while attempting to establish an SSL or TLS connection.

[cobian]

Will check this out.

[arshanskiyav]

Hello
Any news?

[cobian]

Sorry, have not had time to check this out yet. WWorking om some other project but I need to find some time for this.