How to fetch the messages of linkedin user

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C#

Linkedln

Hi,

I wanted to fetch the messages (direct messaging) of linkedin users.

I found a code sample to send the message in this site
https://developer.linkedin.com/documents/sample-code-sending-message

But, I did not any sample to fetch the messages.
However, when I tried to fetch the message with the query "/people/~/mailbox", I got the error
"The remote server returned an error: (403) Forbidden."

But in detail error message, I got ">Access to mailbox denied".

Detail Exception
############################
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<error>
<status>403</status>
<timestamp>1407492655499</timestamp>
<request-id>Q925CD3H4M</request-id>
<error-code>0</error-code>
<message>Access to mailbox denied</message>
</error>
############################

These 2 documentations has listed only the Primary Endpoints "POST /people/~/mailbox" but has not mentioned about GET.

https://developer.linkedin.com/oauth-10a-overview
https://developer.linkedin.com/documents/authentication#oauth2-redirect-uri

Is there any way to fetch the message? Or Is there any workaround?
Any insights or help will be highly appreciated.

Thanks