Based on the information provided in the knowledge sources, it appears that you're encountering an issue related to the HTTPS configuration of Ory Hydra. This error message suggests that your client is trying to make an HTTP request to a server that expects HTTPS connections. To resolve this issue, you have a few options: 1. Ensure your client is using HTTPS: Make sure your client application is configured to use HTTPS when making requests to the Hydra server. Double-check the URL you're using for the token endpoint. 2. Configure Hydra to use HTTPS: If you're running Hydra in a development environment and want to use HTTPS, you may need to configure it properly. Ory Hydra supports running in HTTPS mode without actually accepting TLS connections, which is useful for development or when using a reverse proxy. You can find more information about this in the [Preparing for Production](https://www.ory.sh/docs/hydra/production#tls-termination) documentation. 3. Use a reverse proxy: If you're running Hydra behind a reverse proxy that terminates SSL, you can configure Hydra to fake TLS termination. Here's an example of how to do this in Go:

go    package main     import (      "context"      "fmt"      "net/http"       client "<http://github.com/ory/hydra-client-go|github.com/ory/hydra-client-go>"    )     func main() {      tlsTermClient := new(http.Client)      rt := WithHeader(tlsTermClient.Transport)      rt.Set("X-Forwarded-Proto", "https")      tlsTermClient.Transport = rt       config := client.NewConfiguration()      config.Servers = []client.ServerConfiguration{        {          URL: "<https://hydra.localhost:4444>", // Public API URL        },      }      config.HTTPClient = tlsTermClient      c := client.NewAPIClient(config)      fmt.Println(c.PublicApi.RevokeOAuth2Token(context.Background()).Token("some_token").Execute())       // ...    }     // WithHeader implementation...

This code snippet is from the [Ory Hydra Go SDK documentation](https://www.ory.sh/docs/hydra/self-hosted/go#fake-tls-termination). 4. Check your Nginx configuration: If you're using Nginx as a reverse proxy, ensure that it's properly configured to handle HTTPS traffic and forward it to Hydra. You can find an example Nginx configuration in the [Ory Hydra deployment documentation](https://www.ory.sh/docs/hydra/self-hosted/deploy-hydra-example#install-and-configure-nginx). Remember to always use HTTPS in production environments to ensure secure communication between clients and your Hydra server.