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slow in downloading and sending emails

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My outlook is very slow in downloading and sending emails since last week. I thought there is traffic problem with the ISP, but my co-worker's email using the same office 365 service works pretty good on the same computer(a new outlook profile).


Can anyone help me how to resolve this issue?

All Replies
  • Hello Anson,

    Does the problem reoccur when you create a new outlook profile for your email account?

    To narrow down the problem, please try the following steps when issue reoccuring.

    1. Access your mailbox via OWA at to check if you can send/receive properly.

    2. Create a new Outlook profile on client computer and try again.

    Thank you.

    Jack Sun

  • Hi Jack,

    Thanks for your quick response!

    The access to OWA is also slow, but it works.  I tried to create a new profile but the problem is still there,  I also tested POP and IMAP, same problem.

    I found my iPhone email works good when using 3G service.  since the 3G is from different ISP so I am wondering if any problem with my ISP. but if it is the ISP traffic issue, why my workmate's email is good in the same lan network?  

    I am in China and using 20mb ADSL service from China Telecom.

    Best egards,


  • Hi Anson,

    Thank you for your update.

    Since you can access your mailbox in Office 365 with iPhone using 3G service, it seems that your mail account in Exchange Online works well.

    To narrow down if the problem is related to your company network. You may try to access your mailbox in Office 365 using Outlook client from another network and check what happens.

    Meanwhile, you can also test your network with following links.

    For America use  
    For Asia Pacific use  
    For Europe, Middle East and Africa use 

    Thank you.

    Jack Sun

  • Hi Jack,

    It is better when I try another network.

    Here is the test result. If there is an problem, how should I address ths issue.  It is strange, that my coworker's email works well.

    Speed test statistics


    Download speed: 4612960 bps

    Upload speed: 540688 bps

    Quality of service: 29 %

    Download test type: socket

    Upload test type: socket

    Maximum TCP delay: 737 ms

    Average download pause: 2 ms

    Minimum round trip time to server: 56 ms

    Average round trip time to server: 58 ms

    Estimated download bandwidth: 6320000bps

    Route concurrency: 1.370053

    Download TCP forced idle: 0 %

    Maximum route speed: 9362136bps

    Capacity test statistics


    Download capacity: -- bps

    Download packets per second: --

    Upload capacity: -- bps

    Upload packets per second: --

    Quality of service: -- %

    Packet size: 1000 Bytes

  • Hi Jack,

    In addition to above.   I tested the same ISP service at several locations, same problem.  No problem for different ISP. Since the ISP in use is the most widely used in my area, really need a solution. 


    Because my coworker's email works well, i am gussing if we are approaching different server IP.

  • Jack, can you help?

  • Need Help-

    My email is exremely slow in the office(may take 2 hours for a 5 kb mail)  but my workmate's email works well, same domain, same network.

    When i change to another network of a different ISP, my email works well.

    I have been suffered from this for two weeks, urgently need support

  • Hi Anson,

    I think you need to check if your computer was invaded by virus.
    Or there are some softwares on your computer occupied your network's band width.




  • Hi Anson,

    Since the problem has been narrowed down to your local computer, I would suggest focusing your investigation there.

    As Moka suggested this could be caused by walware on your computer, or this could be a physical problem with the network cable (pinched ethernet cable, cable too close to a power source) or a flapping NIC. This could also be caused by a misconfigured windows firewall or an overly aggressive antivirus program.

    If all else fails it may be quicker to reimage the computer, rather than spending a lot of time trying to track down the difference between your computer and your co-workers computer.


  • i am pretty sure my computer is fine. the service recovered two weeks ago but now the same problem happens again.  I noticed there is an auto change to the server ( today. the red part is not the same as yesterday when i works well.

  • Anson,

    Is your co-worker experiencing the same slow email? Is he connecting to the same server?


  • HI David,

    No he does not,  his account works well on my computer too, under a new profile.

    The sever is not exactly the same, the first 3 digits are not the same. my email server is, while his is

  • Anson,

    Reviewing this thread I see that the last time this happened you were able to access OWA from outside your network without this problem, and you were also able to connect with your iPhone without problem, is that the case this time too? If so, that would show that this isn't a problem with your Office 365 account.

    Since your co-worker can access without problems from your computer in another profile, it would seem to indicate that this isn't a problem with your computer or your network. Rather this seems to be a problem with your local user account itself. Do you use Active Directory on premise? Are there any programs on your computer that interact with your user account specifically? Does this problem present if you create another profile on another computer and try to connect?