Windows Phone, Exchange, and self-signed certificates

I am setting up a Nokia Lumia phone, which runs Windows Phone 7.5 “Mango”. I am impressed with the smoothness of the setup experience, though I had one slight hassle which I do not blame on Nokia or Microsoft because it is is not typical.

I run an Exchange Server (and SharePoint) for test purposes with a self-signed certificate. On the iPhone and I think Android, you just get a warning the first time you connect and after that it all works. Windows Phone though gives you a certificate error when Outlook tries to connect and will not let you proceed further.

Which of these approaches is right is a moot point: convenience versus security I guess.

Fortunately it is not too hard to get Windows Phone to trust your certificates. Here is what I did:

1. Email the certificate(s) to myself on Google Mail.

2. Go to Google Mail in the phone’s browser. For this to work I found I had to use the Basic HTML view, as the mobile view did not let me download the attachments.

3. Open the email you sent to yourself. Tap the attachment. Windows Phone offers to install the certificate, tap to install.

4. Now go back to Outlook and synchronise, everything works.

You will also need this for SharePoint if you want to use Office on the device.

Of course if your Exchange and SharePoint use a certificate from a trusted certificate provider then these steps are not necessary.

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11 comments to Windows Phone, Exchange, and self-signed certificates

  • Andrew

    I am thinking of replacing my iPhone 4 with the Lumina and would be very interested to know how you get on.

  • Windows Phone! I reckon Android is outpacing everything else on the cellphone OS already. I have an HTC cellphone that does everything and more. Or am I deluded?

  • Ole

    Just to let you know, it worked for me..thanks

  • Toni

    It not working Exchange 2007… certificate error 8007270D

  • TJ

    Hi people

    Have tried the above nut get the below error message. do you know how i can overcoem this issue




    Install Certificate contains an executable file. For security reasons, Gmail does not allow you to send this type of file

  • tim

    Just attach the certificate, not a zip or executable.


  • Sheng


    it works on my lumia 800…it really simple atcually..FYI i don’t have to use html browser to open google acc & install the certificates. tq so much…

  • Risto

    Just one simple question. Where do I get that certificate? Our company uses MS Exchange Server, but I can’t connect to that with Lumia 920.
    I keep getting error 85030027. I would love to give a try by emailing that certificate to my phone, but since I’m not an expert in this area, I have no idea where i’d get that certificate?

  • tim

    Either get it from your administrator, or try running IE as administrator and visiting outlook web access. Double-click the padlock or certificate error, Details tab, copy to file.


  • Risto

    Thanks for the advice. I did it this and sent it to hotmail in my phone. Installed the certificate, but no change. Still same error 85030027.
    Any other good ideas?? Spent 600 € for this phone and can’t send/read email from my work server…

  • tim

    Did you restart the phone? If that does not work, I think you will need to talk to your admin.