我在基于WebApp-graph-user sample的应用程序中收到以下错误堆栈。我只是想登录并获取 User.ReadBasic.All 图形权限的令牌。我检查了进入 AcquireTokenByAuthorizationCode 的所有参数，一切看起来都不错（没有空值）。应用程序是使用 .net core 3.1 的 MVC Web 应用程序。
堆：
NullReferenceException：对象引用未设置为对象的实例。Microsoft.Identity.Client.Internal.ClientCredentialWrapper.get_Thumbprint() Microsoft.Identity.Client.Internal.JsonWebToken+JWTHeaderWithCertificate..ctor(ClientCredentialWrapper credential, bool sendCertificate) Microsoft.Identity.Client.Internal.JsonWebToken.EncodeHeaderToJson(ClientCredentialWrapper credential, bool sendCertificate) Microsoft.Identity.Client.Internal.JsonWebToken.Encode(ClientCredentialWrapper credential, bool sendCertificate) Microsoft.Identity.Client.Internal.JsonWebToken.Sign(ClientCredentialWrapper credential, bool sendCertificate) Microsoft.Identity.Client.Internal.Requests.ClientCredentialHelper。 CreateClientCredentialBodyParameters（ICoreLogger 记录器，ICryptographyManager cryptographyManager，ClientCredentialWrapper clientCredential，CancellationToken cancelToken) Microsoft.Identity.Web.TokenAcquisition.AddAccountToCacheFromAuthorizationCodeAsync(AuthorizationCodeReceivedContext context, IEnumerable scopes) in TokenAcquisition.cs + var result = await application Microsoft.Identity.Web.WebAppServiceCollectionExtensions+<>c__DisplayClass2_1+<b__3>d.MoveNext() 在 WebAppServiceCollectionExtensions。 cs + 等待 tokenAcquisition.AddAccountToCacheFromAuthorizationCodeAsync(context, options.Scope).ConfigureAwait(false); Microsoft.AspNetCore.Authentication.OpenIdConnect.OpenIdConnectHandler.RunAuthorizationCodeReceivedEventAsync（OpenIdConnectMessage 授权响应，ClaimsPrincipal 用户，AuthenticationProperties 属性，JwtSecurityToken jwt）Microsoft.AspNetCore.Authentication.OpenIdConnect.OpenIdConnectHandler。
代码：来自 TokenAcquisition.cs - 第 127 行
// Do not share the access token with ASP.NET Core otherwise ASP.NET will cache it and will not send the OAuth 2.0 request in
// case a further call to AcquireTokenByAuthorizationCodeAsync in the future is required for incremental consent (getting a code requesting more scopes)
// Share the ID Token though
var result = await application
.AcquireTokenByAuthorizationCode(scopes.Except(_scopesRequestedByMsal), context.ProtocolMessage.Code)
.ExecuteAsync()
.ConfigureAwait(false);
context.HandleCodeRedemption(null, result.IdToken);