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Free/Busy info not available, out of office assistant "misses server"

Posted on 2015-02-13
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Last Modified: 2015-03-19
Hi experts.

Preamble: Please acknowledge that I am an experienced admin myself - the cause of this problem is no misconfiguration.

We run an exchange 2007 SP3 (with current roll-up) on server 2008 SP2. From time to time without changing anything, the server runs into the following problem: free/busy info cannot be retrieved and at the same time, the out-of-office assistant stops working on any machine domain wide and says "the server is currently unavailable", please see the attached two screenshots.
Screenshot1Screenshot2 Please note: mails are still being received, everything else works.

I have no idea why this happens since
-no reboot took place
-no updates were installed
-no services crash (also a reboot does not help)
-no software was installed, nor did reconfigurations take place
-no related eventlog entries are being produced during that time window
->not at the DCs, nor at the exchange server :(

I only know how I can solve it: simply uninstall and re-install the client access role at the exchange server. Afterwards, it runs for some time (sometimes half a year, sometimes only one week), until it happens again.

Does anybody have a clue about what might cause this?
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Question by:McKnife
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23 Comments
 
LVL 63

Expert Comment

by:Simon Butler (Sembee)
ID: 40607723
The primary reason for that failure is the Autodiscover system is not setup correctly.

Run this command

get-clientaccessserver | select identity, autodiscoverserviceinternaluri

The host name returned should
a. Resolve to the Exchange server
b. Have an SSL certificate that matches the host name

The SSL certificate needs to be trusted by the clients.

If any of those are not correct, then you will see the failures that you are.

Are you using an external trusted SSL certificate on the server? If so then you may have to adjust the configuration of the server to match.
http://semb.ee/hostnames2007

Simon.
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Author Comment

by:McKnife
ID: 40607725
Hi Simon.

Like I wrote in the pre-amble, this is no misconfig for sure. Remember, It can work forever (half a year or more) without having this problem, then it suddenly appears.
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Author Comment

by:McKnife
ID: 40607738
Simon,

get-clientaccessserver | select identity, autodiscoverserviceinternaluri
returns
Identity                       : EXCHANGE
AutoDiscoverServiceInternalUri : https://exchange.ourdomain.de/Autodiscover/Autodiscover.xml
(our server's name is indeed exchange).

And no, we are not using an external ssl cert, but a self signed one.
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Author Comment

by:McKnife
ID: 40607806
News:

Now I tested using https://ourdomain.de/owa
and there, both work, anywhere and anytime.

What could that mean?
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LVL 63

Expert Comment

by:Simon Butler (Sembee)
ID: 40607808
If you browse to that address - do you get a certificate prompt?
If so, that will be part of the cause of the problem.

Self Signed certificates aren't supported for production use with Outlook Anywhere and ActiveSync. You should really change to a trusted certificate.

Simon.
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LVL 53

Author Comment

by:McKnife
ID: 40607814
No, I don't get a certificate prompt. The cert. is trusted and ever has been deployed to all machines.
We don't use active sync or outlook anywhere.

Have you seen my last comment, about both working in https://ourdomain.de/owa ?
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LVL 7

Expert Comment

by:dsnegi_25dec
ID: 40607851
Might be bandwidth issue.

How you are checking this ? internal or External issue.

basically if client is not reaching to server  on timely, you will see this issue.
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Author Comment

by:McKnife
ID: 40607913
Hi.

The server is idling, CPU, RAM, HDD all idle and enough network bandwith is available.
The server is internal.
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Expert Comment

by:dsnegi_25dec
ID: 40608070
Ok, What about user's ?
Can you escalate this thing to network team as well. they will do a connectivity testing & all.
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LVL 53

Author Comment

by:McKnife
ID: 40608087
Users? As I say, it works with any user, any time and anywhere via OWA while it works for nobody using outlook.
I am the network team and the connectivity is all well. Please consider what I do to solve it: I reinstall the exchange component "client access server" WITHOUT reconfiguring anything and all is well for days, months, sometimes years. Had to do this 6 times now and we run it since ex2007 is on the market...
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Expert Comment

by:Will Szymkowski
ID: 40608173
How does your AD and Exchange architecture look like? Do you have multiple sites where Exchange is being hosted or is it a single site etc? Also because this only happens intermittently, when it does happen is there anything in the Exchange logs that reference any issues with communication with Active Directory?

I would also be checking the logs on your DC's are well and ensure that replication is functioning properly.

Also what do the DNS logs say?

Will.
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Author Comment

by:McKnife
ID: 40608332
Hi Will.

Several things can be ruled out. Since I know that resolving this only requires to reinstall CAS, it will not be DNS, nor replication, nor are the DCs involved at all.
It's the exchange server.

The only hint I have is that while it doesn't work in outlook, it still works using owa.
But what does that mean, what is owa able to tolerate that outlook isn't? In what way does it connect differently?
Who can answer that?

The setup is all simple, Single site, almost entirely defaults are used.
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Accepted Solution

by:
Will Szymkowski earned 500 total points
ID: 40608420
As you know there are multiple virtual directories, OWA being one of them. After logging into OWA you are directly communicating with Exchange. When you are using other means of access, like the Outlook Client, there are different protocols that can be used.
- pop3
-imap
-mapi (most common for Exchange 2007)
- outlook anywhere (https)

Now another thing is depending on the Outlook client you are using 2000/2003 you will use Public Folders to distribute free/busy info. If you are using Outlook 2007/10/13 you use EWS for distribution.

Autodiscover finds the service for your client to use and provides the necessary URL's for EWS/OOF/OAB etc.

So that being said your Outlook client is dependent on all of these services to work in order to have all of the functionality while connected to your mailbox.

So when you say you have issues with Out of Office or free/busy, thats why we ask regarding the autodiscover and EWS virtual directories. If these are not working properly then the services will be degraded in your Outlook client.

OWA is different as it is directly communicating with the Exchange server which is why it continues to provide free/busy and Out of Office functionality.


Will.
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Author Comment

by:McKnife
ID: 40608903
I see. It's outlook 2010.
I'd like to gain a better understanding of what in detail owa does as compared to Outlook when it comes to communicating with an Exchange Server. You write "it is directly communicating" - could you maybe be more specific and compare it with Outlook?

And why would the Connection test that you can perform with Outlook (press CTRL and rightclick the Outlook tray Icon) not show any problems at the same time?

I need to solve it til sunday night or I will resort to the reinstall of the CAS role again and once more fail to understand what is happening, I guess :| unfortunately I won't have access until sunday night.
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Author Comment

by:McKnife
ID: 40611153
Just VPNed in - everything started working again without changing anything. I have no clue. Will have to watch it for a while.
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Author Comment

by:McKnife
ID: 40630856
It has returned, though nothing was changed and no reboots took place. Most weird.

Any more tests you can recommend?
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Author Comment

by:McKnife
ID: 40631295
Progress! We are getting somewhere:

In error state, I looked at IIS. It was missing the Application Pool "MSExchangeServicesAppPool" (below which lives EWS) completely, while the file system held the folders unharmed. After repairing (again re-installed CAS), the AppPool is back...

Now what should that mean? How could that AppPool vanish? No one is working at that server, absolutely nothing was changed!?
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LVL 53

Expert Comment

by:Will Szymkowski
ID: 40631336
As stated in previous comments you had no issues while working with OWA as OWA has its own virtual directory which then uses references the OWAAppPool as well. These are all completely separate which is why users are not affected when using OWA. EWS services tons of features when using the Outlook client.

To find out what happened originally to your ServersAppPool you will need to reference the logs in IIS. You will also need to have Configuration Auditing enabled as well. If this was not enabled you will only have limited details.

Enable IIS Auditing

Will.
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Author Comment

by:McKnife
ID: 40632545
Thanks, but as your article mentions: "IIS configuration Auditing is a feature which is available only with IIS versions from 7.5 which is shipped with Windows Server 2008 R2" - this isn't R2. It seems then I don't have a way to audit this, or do I?
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Author Comment

by:McKnife
ID: 40634363
Ok, I think I got it.

It seems to be a race condition. Whenever the IIS World Wide Web Publishing Service (W3SVC) starts too early, this error state happens (and no reboot could heal it). So for some reason, that happened more frequently the last weeks, while it did happen only about once a year, before.

I have set that service to manual start and start it well after the other exchange services using a scheduled task.
I also compared the starting times of the exchange services over the last week (the server does a daily reboot) and they differ a little so it might also be that the server's storage is pretty busy when starting up. We'll take care of that pretty soon when we'll virtualize the whole thing.

I'll leave this open another 14 days and then distribute points (and give a little more insight on it if it does in fact prove to be true).
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Expert Comment

by:Will Szymkowski
ID: 40634441
My mistake, here is the link for enabling IIS7 auditing.
https://technet.microsoft.com/en-us/library/cc732079(v=ws.10).aspx

Also based on your Exchange Server you should not have any issues regarding starting WWW Publishing Service before Exchange services. Enable Logging and see if you can get more details as to why it is failing.

It really could come down to a misconfigured setting or something of that nature with IIS itself. Any changes made to IIS for Exchange specifically should be done via the EMC or Shell, I would recommend not making any changes to IIS directly as you can see what kind of problems it can cause.

I also understand it is nice to find out what is exactly wrong with the server but in the grand scheme of thing building a new CAS server would have been much faster to resolve this issue.

Will.
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Author Comment

by:McKnife
ID: 40634955
Will, this is logging, not auditing. The logging was on already and I had looked at it - it did not reveal anything useful.
"It really could come down to a misconfigured setting or something of that nature with IIS itself." - I disagree. If it works for years with this config, there's nothing misconfigured (actually, it are the default settings). Thing is, software behaves weird sometimes if resources get sparse. So I think IIS for some reason is bugging around with that MSExchangeServicesAppPool, because on startup, the storage is really really busy. There's no reason (or misconfiguration) that would justify that that AppPool gets removed (repeatedly), don't you agree?

I will reveal more details after I see it works for 2 weeks or so.

Reinstalling: yes, as soon as the next exchange server version is out, we'll do that anyway.
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Author Comment

by:McKnife
ID: 40676851
The thing was a race condition. I now start the IIS scripted a little after all other exchange services have started and that seems to have solved it. Will give the points combined with B to Will since he has at least motivated me to gain more understanding of how outlook communicates with exchange.

Thanks!
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