Hi guys,

I`m starting with Exchange and already facing an issue regarding SMTP Service.

I have an app that needs to relay SMTP through my Exhange 2019.

A receive connector has been created, the app IP was allowed into this receive connector, port 587 configured, FQDN mail.domain.com configured as well.

I have this domain.com zone in my internal DNS and of course, an A record pointing MAIL entry to the Exchange Server.

I will paste the script that I`m using to try the SMTP relay at the end of this post.

So, sometimes the relay works and sometimes fails and returns:

Send-MailMessage : The remote certificate is invalid according to the validation procedure.
At C:UsersMYuserDesktopsmtptest.ps1:15 char:9
+ Send-MailMessage @sendMailParams -BodyAsHtml -Credential $cre …
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : InvalidOperation: (System.Net.Mail.SmtpClient:SmtpClient) [Send-MailMessage], AuthenticationException
+ FullyQualifiedErrorId : AuthenticationException,Microsoft.PowerShell.Commands.SendMailMessage

I have two certificates installed in this Exchange Server, one is issued by internal CA and the other one by a public CA. The second one is a wildcert for *domain.com.

My point is, what am I missing? It seems a little weird for me that sometimes work and sometimes dont.

This is the ps1 script that I`m using to try the smtp relay:

[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12

$sendMailParams = @{
From = email address removed for privacy reasons
To = email address removed for privacy reasons
Subject = “Test SMTP Relay”
Body = “Email sent for tests purposes”
SMTPServer = “mail.domain.com”
Port = 587
Encoding = “UTF8”
}

Send-MailMessage @sendMailParams -BodyAsHtml -Credential $credential -UseSsl

Of course, the certificate is valid, is assigned to SMTP Service in Exchange Server and is TLS1.2.

The mail.domain.com resolves for Exchange Server IP and the Application can reach the server using internal IP and mentioned port.

Anonymous user is allowed for now in receive connector.

Thanks in advance

​Hi guys, I`m starting with Exchange and already facing an issue regarding SMTP Service.I have an app that needs to relay SMTP through my Exhange 2019. A receive connector has been created, the app IP was allowed into this receive connector, port 587 configured, FQDN mail.domain.com configured as well.I have this domain.com zone in my internal DNS and of course, an A record pointing MAIL entry to the Exchange Server. I will paste the script that I`m using to try the SMTP relay at the end of this post.So, sometimes the relay works and sometimes fails and returns:Send-MailMessage : The remote certificate is invalid according to the validation procedure.
At C:UsersMYuserDesktopsmtptest.ps1:15 char:9
+ Send-MailMessage @sendMailParams -BodyAsHtml -Credential $cre …
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : InvalidOperation: (System.Net.Mail.SmtpClient:SmtpClient) [Send-MailMessage], AuthenticationException
+ FullyQualifiedErrorId : AuthenticationException,Microsoft.PowerShell.Commands.SendMailMessage I have two certificates installed in this Exchange Server, one is issued by internal CA and the other one by a public CA. The second one is a wildcert for *domain.com. My point is, what am I missing? It seems a little weird for me that sometimes work and sometimes dont. This is the ps1 script that I`m using to try the smtp relay:[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12

$sendMailParams = @{
From = email address removed for privacy reasons
To = email address removed for privacy reasons
Subject = “Test SMTP Relay”
Body = “Email sent for tests purposes”
SMTPServer = “mail.domain.com”
Port = 587
Encoding = “UTF8”
}

Send-MailMessage @sendMailParams -BodyAsHtml -Credential $credential -UseSsl
 Of course, the certificate is valid, is assigned to SMTP Service in Exchange Server and is TLS1.2.The mail.domain.com resolves for Exchange Server IP and the Application can reach the server using internal IP and mentioned port.Anonymous user is allowed for now in receive connector. Thanks in advance  Read More

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