The attached message was sent a user who has Send-As or Send-On-Behalf-Of rights for this mailbox.

Hey mate me too, this happened over the weekend. I assume you are using exchange online for the services affected ?

My story is is weird though, the customer we are having trouble with a few months ago were having issues for their users when they send an email via the shared mailbox the sent item was going into their mailbox not the senders mailbox.

We ran some commands on exchange online that was suppose to remedy this, it did not.

So i got Microsoft support involved, they also ran the same commands as i did, and it did not work.

Then they said they had seen this issue and it is affecting a lot of customers and will add it to the master ticket and hopefully in the year it will be fixed.

So about last week people with access to the shared mailboxes were receiving this message directly through outlook when they sent as the sender, then after about 2 days the message stopped, then all of a sudden the sent items were going into the correct sent items mailbox..... Great.

But now, any user who has an iphone or ipad using the mail app or even the outlook app when sending from their own account will receive the same error as you have TobyeAIT .

I came here looking for answers also for it seems to be a fresh issue.

TobyeAIT did you have similar issues to me leading up to this problem ?

Just an update to this, this is affecting Android users also in this organisation.

I have put a support call into Microsoft regarding the issue, for this seems to affect mobility devices. As well as the mail client on macs as stated by TobyeAIT.

Hi TobyeAIT, also can you confirm if your users are using outlook 2013 or 2016 on a pc if they have access to a shared mailbox can they actually send as that other account and it goes into the senders sent items and not their own ?

Because this only seems to be affecting my customers that have had the mailboxes set up this way and have access to a shared mailbox.

Thanks

Hi , well that is no good for me, for i want to keep the functionality of being able to save to the senders sent items not the users sent items.

It is bizarre behavior though for the users are sending from their own accounts from their mobile devices, and it does not do this directly through outlook. Must be a mobility thing.

We have discovered that this is purely an issue with O365 and Apple devices may see it more as they may send as another user more often. The issue is if the 2 mailboxes are on different Exchange version as Microsoft may be patching servers on the cloud back-end. I don't know why Microsoft would not have all mailboxes belonging on the same tenancy on the same exchange level.

This is interesting, for i have tested with an android device using the default mail app and also the outlook app and it does the same thing. The only thing that is similar between users is they have access to a shared mailbox( not the same one), and their own personal mailbox is not shared. Any other account that does not have access to a shared mailbox or has given out permissions to be a shared mailbox works fine. And also when you log into mail on an apple device or android device you can only see one mailbox anyway, the only way to see another mail account is to have outlook on a computer or apple Mac and it shows up on the left hand pane.

MS have yet to get back to me via phone, i have been emailing them back and forth, it is such a hard issue to explain over email because they seem to be getting confused and want me to send through screen shots of the users mail profile with their shared mailbox, yet none of them have a shared mailbox arrgghh.

Thanks for your help Archie Bald

Thanks