Received response{code=400, message='Bad Request'} when trying to get access token.

[Delcom130]

I dug deeper in my issue:
#993 (comment)

I am just trying to get the sample code on this site to work.
scribejava/scribejava-apis/src/test/java/com/github/scribejava/apis/examples/TrelloExample.java / .
I see that my POST to get an access token we returned with a {code=400, message='Bad Request'} response.
The following code is from the the latest version of scribejava api. (scribejava-8.1.0)

Here is the code involved in the error:
(Code from OAuth10aService.java)
final OAuthRequest request = prepareAccessTokenRequest(requestToken, oauthVerifier);
try (Response response = execute(request)) {
return api.getAccessTokenExtractor().extract(response);

(Values from Debug)
requestToken = com.github.scribejava.core.model.OAuth1RequestToken@a*******
oauthVerifier = https://trello.com/1/OAuthAuthorizeToken?oauth_token=******************

(Code from OAuth10aService.java)
return api.getAccessTokenExtractor().extract(response);

Values from Debug)
request= @request(POST https://trello.com/1/OAuthGetAccessToken)

response{code=400, message='Bad Request', body='null',
headers={null=HTTP/1.1 400 Bad Request,
X-Dns-Prefetch-Control=off,
Server=globaledge-envoy,
Access-Control-Allow-Origin=*,
Access-Control-Allow-Methods=GET,
PUT, POST, DELETE,
X-Permitted-Cross-Domain-Policies=none, Referrer-Policy=strict-origin-when-cross-origin,
X-Frame-Options=DENY, Strict-Transport-Security=max-age=63072000;
preload, Access-Control-Expose-Headers=x-rate-limit-api-key-interval-ms,
x-rate-limit-api-key-max, x-rate-limit-api-key-remaining,
x-rate-limit-api-token-interval-ms,
x-rate-limit-api-token-max, x-rate-limit-api-token-remaining,
X-Trello-Environment=Production, X-Trello-Version=1.2333.0,
Surrogate-Control=no-store, Content-Length=15,
Expect-Ct=report-uri="https://web-security-reports.services.atlassian.com/expect-ct-report/trello-edge",
max-age=86400,
Content-Type=text/plain; charset=utf-8, X-Envoy-Upstream-Service-Time=8,
X-Content-Type-Options=nosniff, X-Download-Options=noopen,
Pragma=no-cache, Date=Sun, 24 Jan 2021 15:53:40 GMT,
Access-Control-Allow-Headers=Authorization, Accept, Content-Type, Cache-Control=no-store, no-cache,
must-revalidate, proxy-revalidate, X-Xss-Protection=1; mode=block, Expires=0,
}}