Hi,

few months ago I created a new domain child in my environment, ran prepare all domains  created a new mailbox on domain child and was working till exchange stopped working. after I tried to fix I made a new account, exported emails to new account and started to work. today that new account happened the same. so Worked good on OWA, but outlook doesn't work , the rest are working good, I have 500 mailboxes multiple domains. just happen on this account.    what could be the problem ?

Please explain all the details about "Outlook doesn't work".

Hi Srjohny,

Thank you for your question.

Please answer Eds question.

In addition, we could run the following command to check if Mapi is ture.

Get-CASMailbox <this specific account>

Then we could refer to the following link to repair the PST file to check if the issue persist:

https://support.office.com/en-za/article/Repair-Outlook-Data-Files-pst-and-ost-64842a0a-658a-4324-acc6-ef0a6e3567cd

If there are any questions regarding this issue, please be free to let me know.

Best Regard,

Jim

Doesn't sync. I got that message . but worked good till friday and after 2 hours that problem happened started work again .it's weird

I would disconnect the mailbox from the account (Disable-Mailbox) and reconnect it again (Enable-Mailbox).  From your description it appears that that mailbox may have a corrupted attribute in AD.

Hi srjohny,

Thank you for your question.

Do you mean outlook is not synced which is your problem?

If that, when the email could be synced, we could check if email was synced by OWA. We could also check other client to check if the issue persist.

If there are any questions regarding this issue, please be free to let me know.

Best Regard,

Jim

I'll test next time happens.

Today I have again the same problem . it has been working good, today is offline. 

Hi srjohny,

This issue was caused by pst, we could refer to the following link to repair PST file to check if the issue persist:

https://support.microsoft.com/en-us/kb/272227

If there are any questions regarding this issue, please be free to let me know.

Best Regard,

Jim

Hi Jim, it's not possible to be Pst, because I have this account configure in 3 users and all has the same problem. if it was the pst just happens one workstation 

No server performance problems?  This will happen when you max out CPU, for example.

I'm installing Cumulative updates, maybe solve the problem

Hi Jim, it's not possible to be Pst, because I have this account configure in 3 users and all has the same problem. if it was the pst just happens one workstation 

Hi srjohny,

Did you mean the 3 user accounts have same issue which outlook could not be synced? Or you have mount the PST on 3 user account?

Did OWA sync email when outlook lost connectivity?

We want to repair PST is that you have created a new account and mount PST file, the issue could not be caused by account. We suggest you try to repair PST to check if the issue persist.

If there are any questions regarding this issue, please be free to let me know.

Best Regard,

Jim