OWA access gives error HTTP 400 bad request

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Hi all,

We are having exchange server 2007. And we need to access mail box from outside.

Whenever we are putting https://server.domain.com/owa in IE 6, exchange 2007 login page opens, but after loggin on, it gives error of HTTP 400 bad request.

But whenever I am using firefox to access same, it works fine.It opens very well.

Can somebody knows solution of it?




Johan Veldhuis [MVP]


Check the following:

- is IIS running

- can you access the default IIS 6 page

- can you access it from internal ?



blog: www.johanveldhuis.nl

Rock Wang– MSFT

Dear customer:

IIS returns a 400 error code when the request is malformed. Though there are a variety causes for this error, the most common reason is that the request does not comply with RFC 2616. For example, if the request is made in HTTP 1.1, RFC 2616 requires that the request include a Host header. The simplest HTTP 1.1 request would look similar to the following:

GET / HTTP/1.1

Host: example.contoso.com

You can use WFetch to issue such a custom-built request. Most HTTP clients adhere to HTTP RFC 2616 and issue well-formed requests. However, if you are developing a custom HTTP client and are experiencing HTTP 400 problems, use WFetch to make test requests.

To issue a simple HTTP 1.1 request using WFetch

1.Start WFetch.

2.From the Advanced Request list box, click Raw Request.

3.In the box, type the following text, where ComputerName is the name of your server running IIS:

GET / HTTP/1.1\r\n

Host: ComputerName\r\n


4.Ensure that the Host box contains the same ComputerName as noted above.

5.Click Go.

6. Please send the result to the forum for analyze.

This sends the most basic HTTP 1.1 GET request to the server.

WFetch tool is inclued in IIS 6.0 Resource Kit Tools (IIS 6.0), you can download it from the following link:


Hope it helps. If anything is unclear, please feel free to let me know.

Rock Wang


Hi johan,

Below are the answers:

1. IIS is running.

2. For access default IIS page, I am getting following error: Type https:// at the beginning of the address you are attempting to reach and press ENTER. HTTP Error 403.4 - Forbidden: SSL is required to view this resource.

Internet Information Services (IIS)

3. Yes i can access internally very well.

And strange thing that it is wokring fine with Mozilla Firefox browser. From IE 6.0 it is not working.




Hi Wang,

thanks for your reply.

But this thing I have to do on all the computers? or for testing I have to do on one machine.

Also strange is that it is working well with the Mozilla Firefox browser.

Rock Wang– MSFT

Dear customer:

You just only test on your problematic client.

In addition, Please help to collect the IIS log by the following steps:

1). On Exchange Serves, open IIS MMC, right click Default Web Site and then click Properties.

2). Click Website tab and then check Enable logging.

3). Stop the Default Website and RENAME the existing IIS log files under C:\WINDOWS\system32\LogFiles\W3SVC1.

4). Restart the Default Website and reproduce the problem, which will generate new IIS log file with the exact error.
5). Wait for a while so that IIS Log can be synced. And then go to the following folder on Exchange Server: C:\WINDOWS\system32\LogFiles\W3SVC1.

6). Send me the log files to my working email address v-rocwan@microsoft.com. And please let me know the alias of the user who encountered the issue.

Please enable the IIS log, reproduce the issue and then send the IIS log to me. To do so:

a. Open IIS MMC, right click Default Web Site and then click Properties.

b. Click Website tab and then check Enable logging.

c. Click Properties button. On Advanced tab, check all check boxes. On General tab, you can find the path for IIS logfile.

By default, the IIS log files are located in c:\windows\system32\logfiles.

Description of Microsoft Internet Information Services (IIS) 5.0 and 6.0 status codes


Note: when you send e-mail to me, please add the subject of the post.

Rock Wang


Apologies for jumping into this thread, but I'm having an almost identical problem with Exchange 2003 SP2 on Windows Server 2003 R2 (FE/BE setup).

Our IE6 clients are unable to login to OWA when hitting OWA via a hyperlink from our corporate intranet (which is ASP.net based and uses IWA, and is SSL secured), but when they hit the OWA URL directly everything is fine (from IE6). Firefox/Safari uses are having no problem at all - either way?

I'd be interested to know if you find a solution (there are more details on my findings at http://forums.msexchange.org/Form_Based__and_Integrated_Windows_Authentication_Clashing%3f/m_1800487428/tm.htm).

Many thanks,



Hi c1st,

My problem is solved by just upgrading IE 6.0 to IE 7.0. It was a very simple solution.

But I dont know why its giving problem in opening in IE 6.0. May be not compatible with exchange 2007.

May be your problem also can be solved by upgrading IE. Let me know if it solves.

I am also trying another solution, since I dont want to upgrade to IE 7.0 because of some compatibility issue with our intranet website.





Thanks again for letting me jump in - unfortuantly, I get exactly the same problem in IE7? It really does seem to be down to IE clients, irrespective of location (WAN/LAN), host OS and IE version; all non-IE browsers are not seeing the problem.

I note that there was an Microsoft MSFT in the thread further up - I was wondering whether he was able to solve your problem (as the thread stopped after the MSFT's last post and suggestion)?

I'll let you know if I ever get to the bottom of this.




Does it works with the option " use Windows integration verification" radio button unchecked in the ie7 advanced settings?


Hi and thanks for your reply...unfortuantly not - makes no difference. I have been working on this off-thread with a member from msexchange.org and we have pretty much tried everything.

We deleted and re-created all the Exchange virtual directories yesterday, on both FE and BE...but no change.

The other member has used IEWatch and thinks its something to do with the (prior) NTLM authentication into our intranet (which is probably what you were getting at above?).

To re-iterate, if users hit the OWA URL directly everything works fine; if they load our intranet first, launch OWA via a hyperlink that opens in a new window and then login, it fails (it also fails if you type the OWA URL directly into the same intranet browser window as our loaded intranet). All the latter applies from either the LAN or the WAN.

However, if you use a non-IE browser, everything works fine - from LAN or WAN. Our coroporate users run in a locked down environment where our intranet loads as the home page and they don't have access to the Run... command. Thus, its actually quite difficult for then to launch the OWA URL directly. Thus, the new window hyperlink from our intranet.

If we tell IIS to use only Basic Authentication on the default web site (where our intranet is), everything works fine too.

Its almost as if the IWA on the default web site is stopping successful login to OWA - which is where we are concluding that its a NTLM issue.

Our next step will be to switch the LAN users to use Kerberos authentication and set a specific SPN.

The only other thing that's odd is when we switched the default web site back to IWA only, we were prompted to cascade down the values of " UNCPassword" and " AuthFlag" to the Exchange virtual directories - we didn't do this? Do you have an opinion on this?



Mitesh Sura

Try this, it worked for me.

I had windows authentication on server (win2003, iis6.0), I was not able to access intranet url from ie6.

As mentioned earlier by someone, I unchecked the enable integrated windows authentication in the secutiry section of advanced tab in ie6, it did the magic... everything is running smooth.


Hi and thanks for your message - we have tried enabling and disabling integrated windows authentication, and neither make any difference.

We've actually brought forward an exchange server hardware migration, in the hope that a new server and new OS/exchange install may solve the problem. The current Exchange BE server has been upgraded from Win2000 and Exchange 2000, so there could be issues buried deep in the registry (we hope).



Hi all,

We are having exchange server 2007. And we need to access mail box from outside.

Whenever we are putting https://server.domain.com/owa in IE 8, exchange 2007 login page doesn't open, it gives " The page cannot be displayed" Note that before I have installed the IE 8 OWA was working properly.

Can somebody knows solution of it?





I'm having the same issue. I tried everything it's only with a handful of machines. They are running IE8 with all the latest updates. They can connect to OWA with firefox but not IE. I tried uninstalling and reinstalling IE8 and that didn't work.
Outlook version
Outlook 2013 64 bit
Email Account
Exchange Server 2010
Posting my fix for others... In my case I fixed this by changing the '.Net CLR Version' of the MSExchangePowershellAppPool from version 4 to version 2.

I too struggled for hours on this one, on no other site have I seen mention of what worked for me, I hope it helps...
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