Hello guys,

We are experiencing an issue where automatic replies (Out of Office) cannot be configured via the Outlook desktop client for users with Office 365 mailboxes in a hybrid Exchange environment. The same operation works flawlessly in Outlook Web App (OWA).

If I open the Outlook Desktop Client and try to configure automatic Replies for an o365 Mailbox, I get this Error:

"Your automatic reply settings cannot be displayed because the server is currently unavailable. Try again later."

What Works:

• Accessing automatic replies via Outlook Web (OWA) works as expected.
• On-premises mailboxes (Exchange Server) do not show this issue – replies can be set from Outlook desktop client without getting the Error code mentioned above.

Do you possibly have a solution for this?

Microsoft clearly states that the free hybrid license is not allowed to host mailboxes. But what about mailrelay can that be used with the free hybrid license? Any links from ms stating this appreciated

We currently are setup with a hybrid environment with one Exchange 2019 server. I would like to introduce a second one to provide redundancy for mail relay, as we have a few applications that we can't relay direct to Exchange Online.

In terms of adding another hybrid server, I understand setting up the server and running the hybrid wizard, but how do you handle mail flow between on premise and cloud? As it stands our external namespace corresponds to an IP that then NATS to our first hybrid server. Is this where you would typically use a load balancer? If that isn't an option, I'm guessing the only other would be to update the NAT rule to point to the second hybrid server on an as needed basis?

Apologies if this isn't clear, I'm not a Network person, just trying to figure out how to get a second hybrid server in place.

I’m currently migrating from Exchange Server on-prem to Exchange Online (Hybrid setup for now), and I've encountered an issue with legacy devices (e.g., multifunction printers, line-of-business apps) that only support basic SMTP auth or unauthenticated relay. These devices need to send email to external recipients.

From my research, it seems that the long-term solutions are fairly limited due to Microsoft deprecating Basic Auth and pushing for Modern Auth for SMTP connections.

The two options I’m considering are:

1. Internal SMTP relay server (e.g., IIS SMTP, Postfix, etc.)
   • Accepts mail from internal devices
   • Configured with a connector in Exchange Online that allows relay based on source public IP address
   • Routes mail to EXO over port 25 (unauthenticated, but secured by IP-based connector)
2. Third-party SMTP service (e.g., SMTP2GO, Mailgun, SendGrid)
   • Devices send mail to the external service, which handles authentication and external delivery

While I’m aware that third-party services are an option, I’m not in favor of going that route.

That said, I’d prefer a solution that involves an internal relay. Are there any additional options or considerations I might be missing? I understand that Modern Auth over port 587 is the ideal path, but that’s not feasible for these legacy devices.

Site A: 4 Nodes Site B: 4 Nodes Site C: Witness

What happens if the network between site A and B suddenly gets interrupted while both sites maintain full connection to site C?

Does the PAM just stay where it is or is there any decision making going on?

So I went manage mailbox delegation for a shared mailbox and saw this. Any ideas???

Edit. Deleted user. I’d never seen it before. Kind of freaked me out. 🙄🤣

So far I have seen this on only one mailbox when attempting to change any properties. I have no idea where these attributes are located, or why they would be set in the first place. I didn't know it was even possible to set these for a user mailbox.

Has anybody ever run into this?

Hi,

I need to move those mailboxes to the new databases.

What happens when you are moving a gigantic mailbox and backup starts? Will it break anything? Will backup fail because it isn’t a completed mailbox?

Hi,

I need to move those mailboxes to the new databases. I am concerned about the size of transaction logs. AFAIK, the EAC uses the uses the arbitration mailbox to manage moves, which generates TONS of transaction logs, which may fill up your disks very quickly.

Instead of , I will use the New-MoveRequest command. is it correct ?

My other question is : DB01 - old database , MDB01 - new database

already defined in DB01 backup. should I add the new database into the backup job before migration? what do you recommend?

Dear collegues, good afternoon. I have a question. We have two datacenters and we are planning to move from one of them to the another data center. Among other things, some Exchange 2019 DAG nodes, which contains passive database copies, will be moved too. There is a high probability that these servers will be offline for up to a week. How do you think to be with the database copies on them? I am concerned about the buildup of replication traffic on active nodes. There are two factors - free space on disks, which contains transaction logs and the possibility that after some time of downtime the databases will become so inconsistent that they will not be able to replicate after being turned on, and i will have to delete the passive copies and create them again. Should i preemtively delete passive copies before downtime to avoid the above potential issues given the uncertainty of the move timing? And after the move create copies again. Or maybe i`m overly cautious? TY.

We have been running Office 365 since 2017 with an on-prem Exchange 2016 server. We use AD sync to sync passwords and account data from on-prem AD to 365.

I would like to get rid of the on-prem Exchange server, but my co-worker claims it is required for the sync between on-prem and 365. Do we really need to have an on-prem Exchange server in order to sync passwords and account data from on-prem Active Directory to 365?

Hello everyone,

I am trying to figure out if there is any way to completely get rid of exchange 2016 on-prem in a hybrid mode. There are no mailboxes on prem, mx records point to 365, mail flow is on 365. The only thing exchange onprem does it sync attributes to AD. Is there anything I can do to get rid of it? Any 3rd party software available to help with this?

Does anyone understand how the permissions groups work on a receive connector within exchange?

The setting I'm talking about is located under the receive connector settings under Security > Permission groups

I'm trying to set up a new receive connector for an SMTP relay, and currently it only works if we have the Permissions Group set to Anonymous. We have another receive connector that is setup and working but it's Permission Group is set to set to Partner and it works just fine. I'm trying to get this new one set to something other than Anonymous but so far that's the only way it seems to work.

Error when we attempt to send message from exchange server managment shell

Send-MailMessage : Service not available, closing transmission channel. The server response was: 4.3.2 Service not available

I can't figure this out for the life of me... Hybrid connector ran flawlessly, full hybrid with modern config setup. Added all the Microsoft ip addresses to our firewall exceptions. However when I go to migrate (using the endpoint the wizard itself made) I cannot search for users by display name. This issue is driving me crazy, and this entire migration process has been way more annoying than I had anticipated. The company I'm doing this for is on exchange 2019 on-prem... but between Barracuda security sitting in the middle and everything from their exchange to their server OS all being 3+ years without a CU has made this interesting.

Any tips or insights on this could be helpful and very appreciated. Thanks!

Hi,

We have Exchange server 2019 DAG environment. Also there are 8 DBs.

Circular logging for DB02 remains enabled. circular logging for other DBs is disabled. Can I disable circular logging for this DB the during working hours? Will there be a negative effect?

I will do it when backup job is not running?

Veeam agent based database backup is being taken. log truncate is enabled.

Hello,

exchange 2019 on-prem:

I have a distribution group called [support@sample.com](mailto:support@sample.com)

Is it possible to send/reply Mails with sender: [support@sample.com](mailto:support@sample.com) ?

I think not, only possible when having a separate user or shared mailbox with "send as" rights.

thx

Hi, I need to permanently remove a synced cloud user, as the account currently has two mailboxes—one on-premises and one in the cloud.

Could you please let me know what will happen to the user's private Teams chats if I permanently delete the M365 cloud account?

I’d really appreciate your help.

I have a very simple question. There is a DB on the Exchange server.

DB database size:2.5TB whitespace:1TB

Takes up 2.5TB of space on disk. Now I will move all Mailboxes to new MDB01. The new database will take 1.5TB space on disk, right? meanwhile I will remove the old database

Hello guys , I'm currently running Exchange Server 2016 and planning to buy an official Exchange Server 2019 license from a Microsoft partner. Can I use that same license to upgrade to the SE version when it's released, or do I need a separate license?

Is the ability to relay anonymous SMTP to EOL going away anytime soon. We send directly to EOL (no relay via on-prem Exchange). Im wondering since they are doing away with basic auth.

Exchange Online to retire Basic auth for Client Submission (SMTP AUTH) | Microsoft Community Hub

setting a transport rule to block attachments with commonly malicious file extensions. an explanation/notification is delivered to the intended recipient. is there any way to use a variable in the explanation delivered to the recipient showing who the sender was?

right now it appears the notifications are being delivered in plain-text; the html formatting i put into the notification is not being processed.

If u wanted to get a sense of what applications, services and/or servers were leveraging your Exchange Server 2016 on-prem mail server (for sending mail either via Exchange Web Services, or SMTP Replay), is there an optimal way to easily pull that list?

In the past I would take a copy of all the Message Tracking logs, as well as the SMTP Send & SMTP Receive logs, import them all into Excel, and massage the logs until I got a list of servers/IP addresses that were involved in routing mail. This would typically take a full day to do with our log volume. I wondered if there was an easier way to pull that info. Either with a different set of logs, or maybe a PS command or script.

This is also the first year we have leveraged Exchange Online for a subset of our systems. Is there a similar way to pull that info? It's not quite the same as on-prem, as I believe we are using App Registrations for at least some of our integration, and possibly SMTP Relay.

Appreciate any guidance...

Hi,

I'm seeking advice to decomission an ancient exchange 2010 server, it's currently running a hybrid configuration with all mailboxes moved to exchange online, I wanted to get exchange management tools 2019 up and running to manage attributes. Reading the documentation it's only supported to do a schema update from exchange 2013.

How would i go about tackling this in the most efficient way possible to get attribute management from the new toolset? Is there an ideal way of accomplishing this? The plan is to keep the local AD that currently has a Entra ID sync on it.

Very thankful for advice :)

FYI, price increases for Exchange Server Subscription Edition and other on-premises Office servers is going into effect July 2025.

Licensing and pricing updates for on-premises server products coming July 2025 https://techcommunity.microsoft.com/blog/microsoft_365blog/licensing-and-pricing-updates-for-on-premises-server-products-coming-july-2025/4400174