Exchange 2019 CU14 Installation keeps Failing at Mailbox role: client access service

Maryam 0

Hello,

I'm fairly new to dealing with servers and the world of IT, so please excuse my ignorance if this turns out to be a simple error, although I have done my research.

Exchange server keeps failing at mailbox role:client access service, error photo attached below. Event ID is 4027 and source is MSExchange ADAccess.

I'm currently working on VMware Workstation with the exchange server set up on a different machine than my Domain controller, and I'm setting up exchange server on a separate user (not Administrator because I kept getting a lot of errors about forest level, and it's not detecting domain) that is part of the domain and member of (Enterprise, Schema and Domain Admins). I've also made sure forest level and domain are 2016. Also made sure to prepare the AD beforehand and passed prerequisites check. Firewall is off, remote desktop is on, and I downloaded the latest exchange server update

As a last resort I used Setup assist, it keeps failing at finding mailbox role, and I'm not sure where to go from there. Only other case I saw similar to this was solved by uninstalling via command line.

Screenshot 2025-02-03 142754 new

Screenshot MODIDIED 2025-02-04 114047

2 answers

Bruce Jing-MSFT 8,560 Reputation points Microsoft Vendor

2025-02-05T06:28:18.11+00:00

Hi,@Maryam

Thanks for posting your question in the Microsoft Q&A forum.

Based on the screenshot you provided, you can see that Exchange is unable to connect to the Microsoft Exchange Active Directory topology service.

When the error occurs, please have a go by manually starting the "Microsoft Exchange Active Directory Topology service" and see if it could help.

Second method: the following blog shares a solution and in the comments section, a user mentioned that after adding the key MinSuitableServer = “1” as suggested in the blog to the Microsoft.Exchange.Directory. TopologyService.exe.config file and then error 4027 stopped (“I added that key and then 4027 and 2142 stopped and all exchange servers worked.”) :)

Exchange 2013 Setup Fails With Error "An exception ocurred while setting shared config DC"

So I would recommend have a look at the article and give it a try to see the result.

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Maryam 0 Reputation points

2025-02-05T11:28:11.3133333+00:00

Hello,

Thanks for taking the time to reply, sadly I have tried the solution provided in the linked article and restarted but nothing changed. However, The Microsoft Exchange Active Directory topology service stops after running a bit with error 1053 popping up.

could the problem be from the DC? Were there any steps i should have followed before Exchange server set up.? On my DC server i created a new zone & pointer in DNS I've also tried creating a subnet in the AD sites & services.

here I modified the log on settings and checked that the Dependencies are running, restarted but still no change

Also, I tried to extend Schema yesterday, and it got a bunch of errors, shown below.

Bruce Jing-MSFT 8,560 Reputation points Microsoft Vendor

2025-02-06T09:27:34.4466667+00:00

Hi，@

I'm glad to hear back from you.

As things stand now, it is likely that any changes made to the structure of Active Directory have caused this issue.

Solution Result:

clean up AD by removing all Exchange-specific schemas. this must be done very carefully.

Restore a backup of the Exchange server before attempting to install Exchange (or reinstall Windows from scratch).

Ensure that the new Windows is not installed and/or configured to have any sites (this can easily corrupt an Exchange installation).

Then install Exchange again (be sure to refer to the official documentation).

https://learn.microsoft.com/en-us/exchange/plan-and-deploy/prerequisites?view=exchserver-2019

If my answer is helpful to you, please mark it as the answer so that other users can refer to it. Thank you for your support and understanding.

Maryam 0 Reputation points

2025-02-10T11:38:55.3466667+00:00

Hello,

Thank you for taking time to reply again, Apologies for the delay, I hadn't gotten a notification about your reply. Before checking your reply, I had given up and decided to uninstall via command line and verified removal from control panel, also used ADSI to Remove Exchange Server attributes & users by following this articlehttps://www.alitajran.com/how-to-remove-exchange-from-active-directory/ but i didn't delete the computer from computer's container in my DC since I'm going to be installing it again immediately.

I tried installing again, at first i got errors concerning AD & forest level but after trying again it worked fine, not sure what changed. Preparing AD was done successfully (schema, prepare AD & prepare domain). However, setup failed again and setupassist still showed same errors, so I tried to remove the watermark from the location specified and it passed in setupassist, but I just got another error in exchange set up and the latest is Event ID: 6027 & 1002, source: MSExchange Certificate Notification.

From reading the error it's telling me to delete an AD configuration manually, I'm just not sure where.

Good news is i no longer get error 1503 when I try running services manually also the Microsoft Exchange Active Directory topology service was running automatically,I ran the Test-ServiceHealth command in Exchange Management Shell and after manually tuning some services on all returned True.However, if I try running setup they're stopped again

And this is the latest setup assist, these are the main ones I noticed, also attached file below.

"DC DNS Host Name","Passed","PDC19.Entercloud.local ","Does not have an FQDN in dnsHostName. This may cause setup to fail." -------------------------------------------------- "Valid Home MDB","Failed","Failed to find any critical mailboxes","Valid Home Server Name","Failed","Failed to find any critical mailboxes"

SetupAssistResults-202502100121.txt

Maryam 0 Reputation points

2025-02-10T11:49:38.6266667+00:00

Forgot to mention I dont have a back up for Exchange server. could the problem be from my DC / DNS..?

I ran the BPA on my DNS and the following came up

1- warning Scavenging is disabled on the DNS server.

2- A lot of warnings with multiple ip's root hint server not responding to NS query.

3-Ethernet0 has only the preferred DNS server configured.

4-loopback address:

problem:The network adapter Ethernet0 does not list the local server as a DNS server; or it is configured as the first DNS server on this adapter.

My boss suggested making another DNS server on my domain controller, what do you think? and if you agree that would require a new server and I would connect to my main domain controller using DNS manager and creating a zone or is there another way.?

Bruce Jing-MSFT 8,560 Reputation points Microsoft Vendor

2025-02-12T09:13:58.21+00:00

hi@Maryam

I am glad to hear from you.

The error message you’re encountering is from a pre-requisite check during the Exchange installation. It means that on the network adapter (Ethernet0), either the local server (the one on which you’re installing Exchange) is not listed as a DNS server, or it isn’t set as the primary DNS server. Exchange requires proper Active Directory name resolution, so the DNS settings must be correctly configured.

Regarding your boss’s suggestion to create an additional DNS server on your domain controller, here are my thoughts:

There’s usually no need to set up an entirely new dedicated DNS server. In most cases, simply adjusting the DNS settings on the network adapter of your Exchange server (or the domain controller hosting the DNS service) is sufficient to resolve the issue. If your Exchange server is also a domain controller or is running the DNS service, you should configure its IP address (or the appropriate domain controller’s DNS IP) as the primary DNS server for that adapter.

2.I recommend starting by checking and adjusting your network adapter’s DNS settings. This should resolve the Exchange pre-requisite requirement without the need to deploy an additional server.

If my answer is helpful to you, please mark it as the answer so that other users can refer to it. Thank you for your support and understanding.

Maryam 0 Reputation points

2025-02-13T13:04:00.1533333+00:00

Hello,

Thank you for writing back, Not sure which error you're referring to but, just to give you the full picture I have 2 servers set up, both on VMware first one is for my [Domain controller, AD DS, DNS]. And my second server has [IIS, AD LDS] no DNS on my 2nd server and that's where I've been trying to set up Exchange server.

Before starting with the Exchange Setup I added my 2nd server to my domain so my preferred DNS is the 1st server's IP and Alternate is 8.8.8.8.

On my first server I set up DNS preferred as its own IP and alternate as 127.0.0.1 originally I had preferred as 127.0.0.1 but changed it back after running BPA (I still get loop back address error).

Should I change anything here.?

If it makes any difference, the user I am currently using on 2nd server is not Administrator (Trying to set up exchange kept failing with errors about forest level, and it's not detecting domain and DC.). I created another user on my 1st server [DC] after adding that user to both Enterprise, Domain & Schema admins I then logged onto my 2nd server.

Only changes I've made currently is tinkering with DNS manager at DC, (when launching nslookup I got default serer: unknown), fixed it by changing interfaces listening from all IP's to only my 1st server's IP. still getting same errors/warning in BPA though.

Should I be deleting the AD configuration mentioned in the setup window.?, also still getting the following line in setup assist:

"DC DNS Host Name","Passed","PDC19.Entercloud.local","Does not have an FQDN in dnsHostName. This may cause setup to fail. -------------------------------------------------- "Valid Home MDB","Failed","Failed to find any critical mailboxes","""Valid Home Server Name","Failed","Failed to find any critical mailboxes

I've been thinking of trying to set a new server, setting up DC and Exchange on it, but I've read this is not advised. Please notify me if there are any changes to be made. Thanks again

Maryam 0 Reputation points

2025-02-13T13:18:38.67+00:00

Hello,

Thank you for writing back, I checked on my DNS settings and this is it currently:

1- my DC server DNS preferred is its own IP and alt is loop-back (I still get loop-back error when running BPA)

2- 2nd server (where I'm setting up Exchange) preferred is my 1st server's IP and alt is 8.8.8.8

2nd server does not have DNS installed and is joined to 1st server domain

should i change anything here.?

Only thing I fixed up in my DC is when launching nslookup in DNS manager default user was unknown changed interfaces to own IP only.

Would installing mailbox role manually make a difference.? Also, even though I've read it's not recommended, but I've been thinking of setting up a new server and installing DC & Exchange on it.

Here's a screenshot from the exchange server, and the line underneath still shows up on setupassist.

"DC DNS Host Name","Passed","PDC19.Entercloud.local ","Does not have an FQDN in dnsHostName. This may cause setup to fail." -------------------------------------------------- "Valid Home MDB","Failed","Failed to find any critical mailboxes","Valid Home Server Name","Failed","Failed to find any critical mailboxes"
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Bruce Jing-MSFT 8,560 Reputation points Microsoft Vendor

2025-02-14T06:52:56.4333333+00:00

Hi，@Maryam

It's good to hear from you and I have a preliminary understanding of your environment. Since a case corresponds to a question, I would like to check with you if your Exchange 2019 CU14 installation issue has been resolved?
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