oauth 2.0 - linkedin access token generation error -

when try generate access token using:

https://www.linkedin.com/uas/oauth2/accesstoken?grant_type=authorization_code&code=xxxxxxxxxxx&redirect_uri=http%3a%2f%2fws-100945%3a9080%2fartisweb%2findex.html&client_id=xxxxx&client_secret=xxxxx 

it's throwing error as:

{"error_description":"missing required parameters, includes invalid parameter value, parameter more once. : unable retrieve access token : appid or redirect uri not match authorization code or authorization code expired","error":"invalid_request"}.

could guide me on issue?

the url looks correct must code expired or reused. make sure code used after receive , use once.

also make sure url-encode in fact parameter values, including client_id , client_secret if/since may contain url-unsafe characters '&' , ' '.