SQL Server 2016 Database Mail cannot send email smtp.office365.com

Question

SQL Server 2016 Database Mail and I get this error: Message The mail could not be sent to the recipients because of the mail server failure. (Sending Mail using Account 3 (2020-12-02T22:03:59). Exception Message: Cannot send mails to mail server. (Failure sending mail.). ) The configuration I use
Server: smtp.office365.com Port Number: 587 Authentication: Basic (An email address and password)

The server has disabled all SSL3 TLS 1.0 and 1.1, enabled TLS 1.2 Also .NET 4.7.1

Still not working...

Answer 1

Hi @drcz ,
In addition, have you ticked “This server requires a secure connection(SSL)” in account tab?
Please refer to this similar thread:

Below is the content for a simple executable registry file that I put together that will make the 2 new settings and the settings already shown on the thread above (i.e. this makes all of the necessary Registry settings*):
Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft.NETFramework\v4.0.30319]
"SchUseStrongCrypto"=dword:00000001

[HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft.NETFramework\v4.0.30319]
"SchUseStrongCrypto"=dword:00000001

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.2]

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.2\Client]
"DisabledByDefault"=dword:00000000
"Enabled"=dword:00000001

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.2\Server]
"DisabledByDefault"=dword:00000000
"Enabled"=dword:00000001
Note 1: SQL needs to be restarted for these settings to take affect but it is better to restart Windows since the new settings will affect .NET 4.x generally.

Note 2: In SQL, the SSL-checkbox must be ticked in the mail profile to use TLS1.2.

Best Regards,
Amelia

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Answer 2

I did used this tutorial https://www.jorgebernhardt.com/disable-ssl-and-tls-on-winserv/ and TLS 1.2 was there.
What was missing were two I did added manually:

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft.NETFramework\v4.0.30319]
"SchUseStrongCrypto"=dword:00000001

[HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft.NETFramework\v4.0.30319]
"SchUseStrongCrypto"=dword:00000001

Also meanwhile I had to add SSL certificate to the server using this tutorial https://www.youtube.com/watch?v=UvoEYqB0tXw&ab_channel=TipsForITPros
In MMC I had to double click the SQL Server and I changed the Account Name https://thesqldude.com/2011/08/03/sql-server-service-does-not-start-after-enabling-ssl-encryption/

thank you!