The client_assertion_type is invalid

I’m following Get an access token | Okta Developer and have completed the below steps successfully:

  1. Generated JSON Web Key Pairs Sets
  2. Previous generated keys have been used to create a service thru the API
  3. Access granted to scope
  4. JWT string has been signed

and after that I’m getting the below error which says client_assertion_type is invalid

~  curl -X POST "" \
    -H "Accept: application/json" \
-H "Content-Type: application/x-www-form-urlencoded" \
-d "grant_type=client_credentials \
& \
&client_assertion_type=urn:ietf:params:oauth:client-assertion-type:jwt-bearer \

{"error":"invalid_client","error_description":"The client_assertion_type is invalid."}%

I have checked the allowed client_assertion_type types, and looks correct, the only issue I noticed is that the Application the moment is created thru API doesn’t get a client secret assigned

Does anybody has any clue about what could be wrong?

Hi @ariel.mendoza,

If you’re following this guide to Implement OAuth For Okta, you should be calling instead of (Remove default from the token URI)
Let us know if that works.