unable to retrieve access token linkedin api

Question

I am applying connect with linkedin. I'm following the step by step guide. To authenticate users, I took help from this.

When the user clicks the connect with linkedin button the user is taken to the linkedin login page. After the user has given access to the account the user is redirected to:

https://www.linkedin.com/uas/oauth2/authorization?response_type=code&client_id=1ba8ogpm9e05&scope=r_basicprofile%20r_emailaddress&state=STATE&redirect_uri=http://127.0.0.1:8088/sandbox/linkedin/test.php

Through this, I get the authorization code. And pass it in the following url

https://www.linkedin.com/uas/oauth2/accessToken?grant_type=authorization_code&code=AUTHORIZATION_CODE&redirect_uri=http://127.0.0.1:8088/sandbox/linkedin/final.php&client_id=1ba8ogpm9e05&client_secret=n7GN09I3F2L3IJD1

Here, the error comes i.e.

"error":"invalid_request","error_description":"missing required parameters, includes an invalid parameter value, parameter more then once. : Unable to retrieve access token : appId or redirect uri does not match authorization code or authorization code expired"

Where am I going wrong? I have double checked my api key and secret key.

Answer 1

https://www.linkedin.com/uas/oauth2/accessToken?grant_type=authorization_code&code=AUTHORIZATION_CODE&redirect_uri=http://127.0.0.1:8088/sandbox/linkedin/final.php&client_id=1ba8ogpm9e05&client_secret=n7GN09I3F2L3IJD1
https://www.linkedin.com/uas/oauth2/authorization?response_type=code&client_id=1ba8ogpm9e05&scope=r_basicprofile%20r_emailaddress&state=STATE&redirect_uri=http://127.0.0.1:8088/sandbox/linkedin/test.php

This both should contain same redirect_uri according to the LinkedIn authentication guide:

Parameter: redirect_uri
Description: Required. Same redirect_uri that you passed in the previous step.
Possible Errors:

• Different redirect_uri than used during authorization code generation
• Passed an invalid value
• Passed an empty or blank value
• Missing the parameter