问题描述：
==================
某公司服务器向客户Exchange 2010服务发邮件时老是不成功，有时退信内容为：
The maximum number of delivery attempts has been reached
或是
The reason of the delivery failure was:417 Temporary delivery error
解决办法：
==============
根据退信搜索到下面这个资料：
SMTP Connector rejected an incoming connection - the maximum number of connections has been reached
SMTP Connector rejected an incoming connection - the maximum number of connections has been reached
根据提示修改默认连接器的进站数，如下命令：
set-ReceiveConnector -Identity "Default" -MaxInboundConnectionPerSource 500
即解决问题。
PS：客户的环境还有一个冰峰的行为管理器，也同时禁用了。