OAuth refresh grant returns 500 internal server error

The openid configuration available at the .well-wknow iri for the NSS identity provider (e.g. https://solid.zwifi.eu/.well-known/openid-configuration) indicates support for the refresh_token grant. However, when issuing a refresh token request that should be valid (see below), the response is Internal Server Error.

curl --location --request POST 'https://solid.zwifi.eu/token' \
--header 'Authorization: Basic <client id:client secret>' \
--header 'Content-Type: application/x-www-form-urlencoded' \
--data-urlencode 'grant_type=refresh_token' \
--data-urlencode 'refresh_token=<refresh token>'

Steps to reproduce:

• Get a client ID, secret and a refresh token. That may be done by inspecting the dynamic registration of a client when logging in with an app for instance.
• Use the credentials to fill in the request above (client ID and secret should be base64-encoded)

Expected result

A 200 response with a JSON object in the body containing a new, valid access token.

Observed result

An internal error

Should this issue be reported here in the NSS repo, or in https://github.com/solid/oidc-auth-manager ?

NB: This is kind of related to https://github.com/solid/node-solid-server/issues/641

从 /token 端点开始，使用针对 OpenID 配置示例提供的 curl 请求，跟踪此仓库如何处理 refresh_token grant。将其行为与相关 issue 以及 oidc-auth-manager 仓库进行比较；完成的标准是有效请求返回 HTTP 200 和新的 access token JSON 对象，而不是内部错误。