2,254 questions with Microsoft Exchange Hybrid Management tags
Internal email undeliverable due to "Corrupt message content"
Hi All, We have an issue with a user where an internal email cannot be delivered. The email reaches everyone else's mailbox except for 1 user. I checked the mail flow rules and there's nothing there that would indicate the email being blocked. Does…

How to set time zone in microsoft teams - Hybrid Deployment
Hello, We are using teams in our organisation, and we're bringing on board some more people who are in different timezones. I've taken a look at this thread here:…
Hybrid agent setup failing on "Validating Hybrid Agent for Exchange usage
Hi, I am setting up a Hybrid Wizard config mail migration from on-prem to exchange online. I am using the Modern Hybrid Topology. I get a Validating Hybrid Agent for Exchange usage error: 20240312_070138.log I have also added the log file for further…

Can't revert from "Mail User" to "User Mailbox"
Hello, One of my users lost complete access to her mailbox, I believe her Office licence got "removed" for 2~ hours then put back but nothing came back to normal... O365 Admin Center shows this message on their profile : Exchange : The…
Exchange Hybrid Wizard Error (413)
Hello, we are running into issues with the Hybrid Wizard. On the last point validation, we always getting the same error and dont know what to do, cuz it says the external server is responding with.... See Log attached. 2025.03.05 08:43:02.035 ERROR…
Public Folder Calendar Creation
We use basic public folder calendars for a number of things. These were originally hosted on on-prem Exchange, and are now on Exchange Online. I normally create them in Outlook, and select 'calendar items' from the list of types. However, I'm currently…
HCW8001 Error: Unable to Determine the Tenant Routing Domain
Encountering the error HCW8001 Unable to determine the Tenant Routing Domain while running the Hybrid Configuration Wizard (HCW). Below are the relevant log entries observed during the process: 2025.03.05 15:09:31.633 10271 [Client=UX,…
Impossible to revert "Mail User" to "User Mailbox"
Hello, One of my users lost complete access to her mailbox, I believe her Office licence got "removed" for 2~ hours then put back but nothing came back to normal... We are using Exchange 2019, Active Directory and Azure. O365 Admin Center shows…

Mitigations Cloud endpoint is not reachable Exchange 2019 Deployment
I receieve below warning during Exchange 2019 deployment Mitigations Cloud endpoint is not…
Mail Flow in Hybrid Deployment When HQ Goes Down
Hello, We currently have a Hybrid Exchange deployment with three Exchange Server 2019 Mailbox servers in our HQ, and we also have a DR site with another three Mailbox servers as part of the same DAG. I already understand how mail flow works between our…
unable to add additional email address
Hi All, I am using an Exchange 2016 hybrid environment. We create users on-prem and then migrate them to Exchange Online. I have a user, ******@contoso.com, and I want to add an additional email address, ******@contoso.com, to this user. When I execute…
Exchange Hybrid Wizard. What settings should be used for cloud mailbox management only. No onboarding required.
My customer has an environment that has on-prem AD accounts syncing to M365 via Entra Connect. Mailboxes are in the cloud. The customer just wants to manage their cloud mailboxes from an on-prem Hybrid Exchange server. I have installed the Exchange…
When changing from Distribution to Security, what is the impact or consequence?
What is the impact or consequences when changing the group type from Distribution to Security group? From: Into: Is the inbound email flow still working or stopped due to the AD group changes from On-premise AD DS? I cannot select the AD Distribution…

How to get all users with alias as subdomain
Hello All, We need to pull a report where users having alias as our subdomains We have around 20k users and we need to filter out them with our subdomains (15). Please suggest a quick and easy to figure it out, pulling out the entire report and checking…
How to fix error Error: CommunicationErrorTransientException:Could not establish trust relationship for the SSL/TLS secure channel with authority
we are running a ybrid environment , we create user mailboxes on our on prem exchange and than migrate the mailbox to exchange online , we have been doing that succesfully up until last week , when it started fsiling for all mailboxes , it stay for the…
Application Impersonation
Hi All, I have received an email from Microsoft stating that the Application Impersonation RBAC role in Exchange Online will be retired in February. I want to identify which applications in my tenant are using this role. Will the script below fetch all…
Removing Exchange on-prem
Hi, We have inherited several sites where hybrid Exchange migrations were executed. Mailboxes have moved to M365 etc, but there is still an on-prem Exchange 2016 Server and ADSync is still in use. We want to get rid of these Exchange Servers as this…
On premise 2016 to exchange online
Hi all, i have a hosted exchange 2016 with 22 tenanats that I need to migrate. I don't want to install AAD connect or hybrid. Is there a way to do it manually by importing a CSV file? Or do a cutover with selective mailboxes?
O365 Sync Issues After On-Premises Exchange Decommissioning
In a transition from a Hybrid environment to nearly full cloud usage, the on-premises Exchange was shut down due to security concerns, following documentation and recommendations while leaving the schema intact. Currently facing issues managing user…
SPF and DKIM is faling as emails are getting forwarded to one Cloud Anti-Phisihing Solution
Hello, We are using EOP as our email Gateway and once internet email reaches to EOP we are forwarding that internet email to one Cloud Anti-Phisihing Solution platform and then again email comes back to EOP but due to this routing when EOP check the SPF…