Request token retrieval failed:

RESPONSE:

Array
(
    [linkedin] => Array
        (
        )

    [info] => Array
        (
            [url] => https://api.linkedin.com/uas/oauth/requestToken
            [content_type] => 
            [http_code] => 0
            [header_size] => 0
            [request_size] => 0
            [filetime] => -1
            [ssl_verify_result] => 0
            [redirect_count] => 0
            [total_time] => 0.00726
            [namelookup_time] => 0.005194
            [connect_time] => 0.007364
            [pretransfer_time] => 0
            [size_upload] => 0
            [size_download] => 0
            [speed_download] => 0
            [speed_upload] => 0
            [download_content_length] => -1
            [upload_content_length] => -1
            [starttransfer_time] => 0
            [redirect_time] => 0
            [certinfo] => Array
                (
                )

        )

    [oauth] => Array
        (
            [header] => Authorization: OAuth realm="http%3A%2F%2Fapi.linkedin.com",oauth_version="1.0",oauth_nonce="a405a53dfdf9da1de43291dd02f44172",oauth_timestamp="1539991838",oauth_consumer_key="81dzxw7porkwt1",oauth_callback="http%3A%2F%2Fmyopencourses.com%2Fusers%2Fsocial_logins%2FlinkedIn_auth",oauth_signature_method="HMAC-SHA1",oauth_signature="luTttgS0wb%2BmSkck4EBwgT6tXSY%3D"
            [string] => POST&https%3A%2F%2Fapi.linkedin.com%2Fuas%2Foauth%2FrequestToken&oauth_callback%3Dhttp%253A%252F%252Fmyopencourses.com%252Fusers%252Fsocial_logins%252FlinkedIn_auth%26oauth_consumer_key%3D81dzxw7porkwt1%26oauth_nonce%3Da405a53dfdf9da1de43291dd02f44172%26oauth_signature_method%3DHMAC-SHA1%26oauth_timestamp%3D1539991838%26oauth_version%3D1.0
        )

    [error] => OAuth callback URL was not confirmed by the LinkedIn end-point
    [success] => 
)


LINKEDIN OBJ:

Array
(
    [linkedin] => Array
        (
        )

    [info] => Array
        (
            [url] => https://api.linkedin.com/uas/oauth/requestToken
            [content_type] => 
            [http_code] => 0
            [header_size] => 0
            [request_size] => 0
            [filetime] => -1
            [ssl_verify_result] => 0
            [redirect_count] => 0
            [total_time] => 0.00726
            [namelookup_time] => 0.005194
            [connect_time] => 0.007364
            [pretransfer_time] => 0
            [size_upload] => 0
            [size_download] => 0
            [speed_download] => 0
            [speed_upload] => 0
            [download_content_length] => -1
            [upload_content_length] => -1
            [starttransfer_time] => 0
            [redirect_time] => 0
            [certinfo] => Array
                (
                )

        )

    [oauth] => Array
        (
            [header] => Authorization: OAuth realm="http%3A%2F%2Fapi.linkedin.com",oauth_version="1.0",oauth_nonce="a405a53dfdf9da1de43291dd02f44172",oauth_timestamp="1539991838",oauth_consumer_key="81dzxw7porkwt1",oauth_callback="http%3A%2F%2Fmyopencourses.com%2Fusers%2Fsocial_logins%2FlinkedIn_auth",oauth_signature_method="HMAC-SHA1",oauth_signature="luTttgS0wb%2BmSkck4EBwgT6tXSY%3D"
            [string] => POST&https%3A%2F%2Fapi.linkedin.com%2Fuas%2Foauth%2FrequestToken&oauth_callback%3Dhttp%253A%252F%252Fmyopencourses.com%252Fusers%252Fsocial_logins%252FlinkedIn_auth%26oauth_consumer_key%3D81dzxw7porkwt1%26oauth_nonce%3Da405a53dfdf9da1de43291dd02f44172%26oauth_signature_method%3DHMAC-SHA1%26oauth_timestamp%3D1539991838%26oauth_version%3D1.0
        )

    [error] => OAuth callback URL was not confirmed by the LinkedIn end-point
    [success] => 
)