Tag: ndr

Android Outlook Message Sending Failure

I’ve been getting a strange error when trying to send pictures within e-mail messages from my Android phone. I say a strange error because there’s literally one entry that comes back when you search for MessageDeliveryFailedException f5f0 — and no pointer at all as to what might have gone wrong. Just a non-delivery report popping into the Inbox on my phone:

     Technical details
     MessageDeliveryFailedException: Could not deliver the message [len=70, data=50005…C090005] sent at 8/25/2020 10:06:28 PM.Failure code: f5f0

I’ve got a reverse proxy with an application firewall and suspected that was the source of my problems. Mostly because errors caused within the Microsoft Exchange system are generally easy to find online. An oddball error is going to come from an oddball source. And I was right — my application proxy log shows an error each time I attempt to send one of the failed messages.

Edited /etc/httpd/conf.d/mod_security.conf and upped the SecRequestBodyNoFilesLimit. Once Apache HTTPD was restarted, I was able to send my messages without problem.

Unable to ‘send as’ from Outlook With Exchange

I’ve had a confounding problem — we have sendmail magicing up millions of e-mail addresses for us, but occasionally we need to be able to send from one of these addresses too. I’ve got a web form that allows text-based messages (html or plain text), but I don’t want to figure out how to upload and attach images via a web form. Until I get around to updating the web form, I just set up a new Exchange mailbox and grant myself full access (which includes send as permission)

Except ever since we got always updating Office 2016, I’ve gotten nondelivery reports when I subsequently try to send from this new mailbox that claim I don’t have permission to send as the user in question. And I’ve verified my access three times. Even added explicit send-as in addition to full mailbox access.

I’ve finally discovered why I get this false error. The ‘from’ in Outlook allows free-form text which then may or may not resolve against an Exchange mailbox. And based on the permissions of the mailbox (or the lack of permissions of the non-resolved mailbox), it may or may not work. So I don’t have permission to send from newmailbox@ourdomain.ccTLD, I do have permission to send from the Exchange mailbox that happens to have that as its primary SMTP address. Sigh!.

When you use offline mode / cached Exchange mode, and an offline address list, the SMTP address doesn’t resolve out to that mailbox. And Exchange quite properly reports an error. To get the whole thing to work (assuming “wait until tomorrow” isn’t a good answer):

First, the offline address needs to be updated (either wait or hit the powershell management console on the server)

Update-OfflineAddressBook -Identity "Default Offline Address Book"

Secondly, Outlook needs to retrieve the updated address book. Within the Outlook client, use send/receive to update the address lists. Then you can send as the mailbox to which you have perfectly configured access.