I want to know how to authenticate the OWA in asp.net

I made a page, I want to authenticate the OWA.

I have been using EWS Managed API.

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owa / service.svc / s / GetFileAttachment? id =
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Inline attachment in the URL of the source was made of.

But should not the picture show in OWA.

Do you access the URL of the picture track is OWA Login page.

Log in and showed the picture.

I'd like to correct this problem.

I'm using asp.net being.

Please help me.