显然，自从Remy在链接的问题中写下答案以来，Office365已停止支持SSLv3（大概是为了避免已知漏洞），现在需要TLS。如果您更改以下两行，则他在原始问题中的答案中的代码将起作用：

Apparently, since Remy wrote the answer in the linked question, Office365 has stopped supporting SSLv3 (presumably to avoid a known exploit) and now requires TLS. The code from his answer in the original question works if you change these two lines:

idSMTP1.UseTLS := utUseImplicitTLS;
TIdSSLIOHandlerSocketOpenSSL(idSMTP1.IOHandler).SSLOptions.Method := sslvSSLv3;

至：

idSMTP1.UseTLS := utUseExplicitTLS;
TIdSSLIOHandlerSocketOpenSSL(idSMTP1.IOHandler).SSLOptions.Method := sslvTLSv1;