Delivery failed 2 attempts: xmsussie@yahoo.com.cn Body of message generated response: 451 Resources temporarily not available - Please try again later [#4.16.5]. 451 無法解析寄件者郵件地址同一封邮件HOTMAIL发过去没问题，而YAHOO老退信。。邮件系统检查过多次没有发现问题。都不知道从何入手了//
