问题描述：

Exchange2007用pop方式收发邮件，发送邮件时提示550.5.7.1 Client does not have permissions to send as this sender。

原因：

这种错误一般是由于那些用户邮箱的 "SELF" account 没有“Send As” 权限所导致。

解决办法：

1. 在Exchange Management Shell下，运行以下命令

[PS] C:\>get-mailbox "User Alias" | add-adpermission -user "NT Authority\Self" -ExtendedRights Send-As, Receive-As

2. 在Exchange Management Console里加"Send As" 权限

======================================

a. Open EMC

b. Expand Recipient Configuration

c. Click Mailbox

d. Right click affected user mailbox

e. Select "Configure Send As permission"

f. Click Add and Find "NT Authority\Self"

g. Select "NT Authority\Self" and click OK

h. Check POP3 connectivity now

PS: EMC的方法Exchange 2007 SP1下有效。