Answer by Kévin Chalet for OpenIddict Decryption of key failure

In OpenIddict 3.0, access tokens are encrypted by default. To fix the error you're seeing, you can either:

• Register the encryption key in the JWT handler options (options.TokenValidationParameters.TokenDecryptionKey).

• Disable access token encryption:

services.AddOpenIddict()    .AddServer(options =>    {        options.DisableAccessTokenEncryption();    });

Note: in 3.0, the recommended option is to use the OpenIddict validation handler instead of the JWT handler developed by Microsoft.