Smtp发送邮件问题
the SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.7.57 Client not authenticated to send mail. Error: 535 5.7.3 Authentication unsuccessful
==============可能原因================
请检查账号是否存在，如果账号不存在可能会出现此问题
SmtpClientAuthentication is disabled for the Tenant.
错误详情：
‘The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.7.57 Client not authenticated to send mail. Error: 535 5.7.139 Authentication unsuccessful, SmtpClientAuthentication is disabled for the Mailbox. Visit https://aka.ms/smtp_auth_disabled for more information. [ZQ0PR01CA0009.CHNPR01.prod.partner.outlook.cn]’
==============方案================
参考文档：
Deprecation of Basic authentication in Exchange Online | Microsoft Learn
在 Exchange Online |中启用或禁用 SMTP 身份验证微软学习 (microsoft.com)
Connect to Exchange Online PowerShell | Microsoft Learn
开启O365 邮箱账号的smtp模式
1. 安装模块
Install-Module -Name ExchangePowerShell
2. 检查安装模块是否成功
Find-Module -Name ExchangePowerShell
3. 连接Exchange
Connect-ExchangeOnline -ExchangeEnvironmentName O365China
登录源：
| Environment | Value |
|---|---|
| Microsoft 365 or Microsoft 365 GCC | n/a* |
| Microsoft 365 GCC High | O365USGovGCCHigh |
| Microsoft 365 DoD | O365USGovDoD |
| Office 365 Germany | O365GermanyCloud |
| Office 365 operated by 21Vianet | O365China |
4. 全局启用smtp
Set-TransportConfig -SmtpClientAuthenticationDisabled $false
5. 检查smtp启用情况
Get-TransportConfig | Format-List SmtpClientAuthenticationDisabled
6. 指定单独邮箱启用smtp
Set-CASMailbox -Identity admin@xxx.partner.onmschina.cn -SmtpClientAuthenticationDisabled $false
原文地址：http://www.cnblogs.com/jerry-li-352/p/16895416.html
