Problem with Teams and Exchange Integration
Hi everyone, My goal is to integrate Exchange Server (Exchange 2016 CU23) with Teams so that the Teams calendar can be used. I have set up Hybrid Configuration (Classic Full Hybrid) and completed the setup without any errors. I have also checked Entourage, and it shows that Exchange has been registered, but the Teams calendar is still not working. Check items: 1. Get-AuthServer 2. Get-IntraOrganizationConnector → Confirm the "Enabled" status. 3. Get-PartnerApplication → Confirm it's enabled. 4. External resolution of the Autodiscover and EWS virtual directories 5. Run Teams Exchange Integration → The only thing that works is "Verifying if the user's mailbox is discoverable by the Teams service," and everything else is fine.The user's mailbox is not discoverable by the Teams service. Please ask your administrators to verify the user has a mailbox and to confirm the connectivity between Teams and Exchange. Does anyone have any other ideas or suggestions to help me? Thanks!
Free/Busy Hybrid Exchange 2019
Hello everyone, I have a hybrid environment with Exchange Server 2019, with a dedicated Exchange application, we renewed the Exchange Auth certificate and then re-ran the HCW, however, free/busy is not working for 365 Pro local users. Has anyone had this problem? Could you help me?Resolved: Hybrid Exchange Duplicate (Ghost) Mailbox Created After Assigning Exchange Online License
Summary During a hybrid Exchange migration, a user’s mailbox failed to migrate and mail flow broke due to a duplicate (ghost) mailbox automatically created in Exchange Online. Root Cause An Exchange Online Plan 2 license was mistakenly assigned to the user before migration. Azure AD sync then provisioned a cloud mailbox, even though the user already had an on-prem mailbox. This caused a hybrid mismatch — the user appeared in both environments, and migration failed with mailbox lookup errors. Resolution Steps Removed the Exchange Online Plan 2 license from the user account. Forced a DirSync (AAD Connect) synchronization. Verified that the mailbox existed only on-prem via PowerShell Get-Mailbox -Identity email address removed for privacy reasons | fl Name,RecipientTypeDetails,ExchangeGuid Confirmed the ghost mailbox was removed from Exchange Online. Re-ran migration batch successfully to Exchange Online. Verification Get-MailboxStatistics -Identity email address removed for privacy reasons | fl TotalItemSize,ItemCount,LastLogonTime Ensure only one mailbox object exists and mail flow routes correctly. Prevention Tips Don’t assign Exchange Online licenses to hybrid mailboxes before migration. Always verify mailbox location prior to assigning any license. Use PowerShell or EAC to check where the mailbox resides (on-prem vs. cloud). Environment Hybrid Exchange Deployment Exchange 2016 On-Premises Exchange Online (M365) Azure AD Connect This issue is not caused by connectors or mail flow settings, but by improper licensing before migration. Removing the license and resyncing resolves the ghost mailbox problem.
Exchange 2016 and 2019 End of Life and Some Interesting Exchange Online Developments
On Oct 14, 2025, Exchange 2019 and 2016 reach end-of-life and Exchange SE becomes the only supported on-premises Exchange server. In other news, we discuss Microsoft guidance for moving to cloud first identity, HVE and ECS and the extension of basic authentication support to September 2028, the introduction of auto-archiving for Exchange Online, and why Microsoft is deprecating the Contact object from Exchange Online. https://office365itpros.com/2025/10/09/exchange-se-news/
Our mail domain isn't safe by default for Exchange Online users
Hello all, Our PR Team requested to force automatic download of pictures for internal letters that are sent by the team. We decide to use GP setting "Automatically download content for e-mail from people in Safe Senders and Safe Recipients Lists" from Office an administrative template. It works fine for users with on-prem mailboxes because our mail domain is in the Safe Senders by default, but it doesn't work for users with mailboxes in Exchange Online. For EO mailboxes, pictures of internal letters are not downloaded automatically in classic Outlook. They have to add "@<our mail domain" to Safe Senders list to download pictures automatically. Any attempts to add the same domain by using Set-MailboxJunkEmailConfiguration fail because "the domain is the default mail domain"! (And should be treated as safe). Headers show that letters are not "Anonymous" but internal. It looks like a bug, or we missed something in our Hybrid configuration. Any ideas? King regards, Dmitry Horushin
Exchange 2019 Mailbox Migration Error - Folder conflicts with Exchange Online folder
Hi Exchange Experts, I'm migrating a small Exchange 2019 environment to 365. Been pulling my hair out becuase of just one mailbox giving this error Error description --------------------------- Error: AggregateMailboxFolderConflictPermanentException: The folder 'Files' conflicts with Exchange Online folder 'Files', please move the messages to another folder and restart the job. Data migrated: 0 B (0 bytes) Migration rate: -------------------------------------- Migration user report: 5/14/2025 12:32:05 PM [MEUP300MB0105] Request processing continued, stage CreatingFolderHierarchy. 5/14/2025 12:32:05 PM [MEUP300MB0105] Stage: CreatingFolderHierarchy. Percent complete: 10. 5/14/2025 12:32:12 PM [MEUP300MB0105] Stage: CreatingFolderHierarchy. Percent complete: 10. 5/14/2025 12:32:12 PM [MEUP300MB0105] Fatal error AggregateMailboxFolderConflictPermanentException has occurred. ---------------------- It seems to be a system folder and I've tried to remove files from it (although there're no files in it) using MFCMAPI tool with no success. Renamed the folder and tried to re-run the migration with no luck. Has anyone experience this issue? any thoughts or tips are much appreciated ! Thank you.
Missing Teams Contacts after Migration
Hello, We are currently migrating mailboxes from exchange 2019 to exchange online. The migration works absolute flawless. Now we have some employees complaining about missing teams contacts that were previously created in Teams only. The MS support told me that this is a teams limitation and the local contacts are gone. I know about unified contacts, thats contacts are synced now between outlook and teams and newly created contacts are stored in exchange online mailbox. But whatabout the old contacts ?? cant believe that theres no workaround to keep this contacts. Do you know something about this ? Rene
Exchange 2016 to SE and Exchange Online questions
Hi, We're currently in the process of migrating from Exchange 2016 to Exchange Subscription Edition (SE), along with moving a portion of our mailboxes to Exchange Online. We have approximately 3,000 mailboxes, and around 2,000 of those will eventually end up in Exchange Online—for various reasons (don’t ask why…). I have a few questions I'd like to clarify and hope you can assist: Exchange On-Premises Questions: If a user mailbox is moved to Exchange SE, can they still access shared or user mailboxes that remain on Exchange 2016? Do we need to migrate them in the same batch to preserve access/permissions? (should't be an issue in the same Exchange Org right?) If a shared mailbox is migrated to Exchange SE while the user mailbox remains on Exchange 2016, will access still work? Do we need to point the Hardware Load Balancer (HLB) to the new Exchange SE servers before mailbox moves to allow proper client connectivity and proxying back to Exchange 2016? Or is it okay to keep the HLB pointed to the Exchange 2016 servers until all migrations are complete and then switch it over? Proxy upwards from Exchange 2016 to Exchange SE? What’s the best practice here? Pros/cons? Exchange Online Questions: If we want all outbound mail to go through the on-prem Exchange environment—even for Exchange Online mailboxes—is this configured via the Hybrid Configuration Wizard (HCW)? Is the Litigation Hold status preserved when migrating a mailbox to Exchange Online? Can a mailbox hosted in Exchange Online access a shared mailbox still residing on-prem? (Should't be an issue right?) Can an on-prem mailbox access a shared mailbox that has been migrated to Exchange Online? For mailboxes with Full Access or Send As permissions (e.g. user mailboxes tied to shared mailboxes), do they need to be migrated together in the same batch to retain functionality? We’ll be using native Microsoft migration tools (no 3rd-party solutions). If I recall correctly, separate migrations will still allow Full Access?!?, but Send As may not work properly unless migrated together. Is that still accurate?
