This issue can also be referred to as how to grant the Send As permission for a mailbox in exchange
Today, one of our customers is experiencing the following problem. After that, he found a lot of information on the Internet and failed to solve the problem. I now share the solution.
You can receive mail using Exchange or Foxmail POP3 mode, but sending a message prompts 550.5.7.1 Client does not has permissions to send as this sender
When you use Exchange Mode, you send and receive messages correctly.
Answer, when you meet the above problem, you can refer to other people on the network solution: first give you the master of the link
Http://blog.5dmail.net/user1/1/2010415115937.html
Http://zzy.my/blog/post/2010/12/31/Exchange-pop3sod.aspx
http://2785903.blog.51cto.com/2775903/1040475
Http://tech.cncms.com/fuwuqi/qita/47060.html
Http://www.ithao123.cn/content-10153578.html
The approximate method is to say that both of these
Workaround:
1. under Exchange Management Shell , run the following command
[PS] C:\>get-mailbox "User Alias" | Add-adpermission-user "NT authority\self"-extendedrights Send-as, Receive-as
2. Span style= "FONT-SIZE:10PT;" > exchange Management Console " Send as "  permissions
======================================
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
I think the above links, we have seen a while, should be able to solve the problem. If you're lucky, like me, take a look at my method. I use the method above, has been prompted to deny access, can not modify the permissions of the agent.
So refer to the following link, directly on the Ad server to modify permissions, this is the method of crime. Direct set self has the Send As (additional proxy send) permission in place of the customer
Http://tech.cncms.com/fuwuqi/qita/47060.html
The customer's environment is Exchange 2010, and the result is still to use this method, sad.
This article is from the "Technology sharing" blog, so be sure to keep this source http://xiaoyuanzheng.blog.51cto.com/7269200/1708905
About Exchange uses Foxmail under POP3 unable to send mail exchange Mode OK