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"Cannot Send Mail" error message via iPhone

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I have multiple users with iPhone's, HOWEVER only ONE user that is getting the "Cannot Send Mail" "An error occurred while delivering this message" error, when sending mail from his iPhone. He hits "OK", eventually the mail goes through. However this happens more than once per day for this user and this error gets annoying. Of all people, this is the owner of our company. We used to host our own mail via Exchange 2003 on our own server without any problems on any phones. We have Blackberry, Android and iPhone's.

I have tried many things to get this error to go away, including restoring the iPhone, deleting the account, turning off the phone, then setting up the account again. Initially the account sets up fine. But then the errors return when trying to send mail. The error's appear to be intermittent.  Whether he's connected via WiFi or 3G.

After the account sets up. I've gone back in and changed the Server name to to try troubleshooting further, to see if that makes a difference. However it changes itself back to the name, which is the name it uses after the initial setup completes. The server name on my phone is different after I enter, it changes to ( I am in Pennsylvania, owner with problem is in Virginia) Please help.

All Replies
  • Hi caddant,


    Given to this situation, I would like to suggest you check the Server name that used to manually setup the account on user's Iphone by following the section Finding My Server Name in the links below:


    If the issue still persists, please help me to collect the following information to narrow down this issue:

    1.Did this account have the same issue on other mobile device such as an Android device?

    2.Did this account have the same issue if he connected his account via POP or IMAP on his Iphone?
    3.Did other users in Virginia have the same issue?


    Jolin Qiao


    1 out of 1 people found this post helpful.

  • I've already used the link you posted in the past while trying to troubleshoot this. First let me preface this with, this account sets up automatically and successfully without any need for manual input of server name. However, since we are having this continued problem, I've tried using the manual method. After we input the correct server name per our settings, eventually the server name changes itself back to the server name it found automatically.

    To answer your questions

    1.Did this account have the same issue on other mobile device such as an Android device? User does not have Andriod device.

    2.Did this account have the same issue if he connected his account via POP or IMAP on his Iphone?

    3.Did other users in Virginia have the same issue? Per my original post, no other users anywhere are having this issue. I am only person not located in VA. We have Blackerry's, Andriods and iPhones and this particaular iPhone is only one with isssue. This IPhone also worked with our old Exchange server WITHOUT any issues.

    I will also add that this same issue occurs on his iPad...

    Seems as though there is a problem with his account in general and has nothing to do with any iphone or ipad?? not sure how to resolve that though. We have been very recently migrated from our own hosted exchange server 2003 to Office 365.

  • Hi caddant,


    Given this situation, I would like to suggest you follow the steps to narrow down this issue:


    1.Please try to sign in your exchange online account from, and check if user will meet the same issues when sending emails.

    2.Ptry to configure this account on an Windows Phone or Android device to see whether the same issue can be met.


    In addition, could you please provide a screenshot about the detailed error message to us for a clear view and further troubleshoot?


    If there are any resutles and updates, please feel free to let me know.


    Jolin Qiao

  • Hi caddant,

    How are things going?

    If there are any questions, please feel free to post.

    Jolin Qiao

  • I've contacted Office 365 support request. The case has been escalated to to higher level. We are still having the issue. No answer at this point and time after jumping through all the required hoops. We can close this on this end.

  • Hi caddant,
    Thanks for your update.
    Since you have submitted a service request, would you mind sending us your service ID via private message? We recommend you to do that so that we can help monitor your case.
    • Go to the Your details section on the right side of the community site.
    • Click Private messages.
    • Click the subject title of the response to read the message.
    • You can reply by using the form in this display.
    • Click Submit Reply.
    Ella Huang
  • Hi caddant,

    I have checked the service request for you. I found that the service request had been closed. You can check if everything is OK.


    Anna Shi

  • Was this very resolved? I am having somewhat of the same issue

  • Yes our issue was resolved. After contacting MS support, they found that, they had to throttle back their servers, this seemed to solve the problem, However, one thing to also try on your end is it turn off PUSH notifications and just use the FETCH setting, set to 15, 30, or however many is acceptable to you. Hope this works out for you.

  • Hi caddant,

    Thanks for your sharing.

    I believe that other customers have the similar issue will benefit from the information you shared.

    Moreover, if you have any other questions when using Office 365, please post a new thread in the forum. We will glad to provide any assistance.

    Hi Sanjay149,

    You can try the solution caddant provided. If the issue persists, please post a new thread in the forum with detailed information about the issue, we will glad to help you to resolve it.

    Thanks for your understanding.


    Anna Shi