failed to fetch registryconnection refused？

### Description

After I configured the java plug-in in apisix, I performed the related configuration according to the documentation, but there was an error that could not connect

the error is:

the apisix config :
```
{
"id": "483159253050196671",
"create_time": 1697514956,
"update_time": 1697538848,
"uri": "/*",
"name": "java-plugin-demo",
"priority": 1,
"methods": [
"GET",
"POST"
],
"plugins": {
"ext-plugin-pre-req": {
"conf": [
{
"name": "TokenValidator",
"value": "{\"validate_header\":\"token\",\"validate_url\":\"https://www.sso.foo.com/token/validate\",\"rejected_code\":\"401\"}"
}
]
}
},
"upstream": {
"nodes": [
{
"host": "192.168.97.25",
"port": 1004,
"weight": 1
}
],
"retries": 1,
"timeout": {
"connect": 6,
"send": 6,
"read": 6
},
"type": "roundrobin",
"scheme": "http",
"discovery_args": {
"group_name": "",
"namespace_id": ""
},
"pass_host": "pass",
"keepalive_pool": {
"idle_timeout": 60,
"requests": 1000,
"size": 320
}
},
"labels": {
"API_VERSION": "x"
},
"status": 1
}
```
the apisix config:

```
ext-plugin:
# path_for_test: /tmp/runner.sock
cmd: ['/usr/local/jdk/jdk-11.0.17/bin/java', '-jar', '-Xmx1g', '-Xms1g', '/usr/local/apisix/demo-0.0.1-SNAPSHOT.jar']
```

### Environment

- APISIX version (run `apisix version`):2.15-centos
- Operating system (run `uname -a`):
- OpenResty / Nginx version (run `openresty -V` or `nginx -V`):
- etcd version, if relevant (run `curl http://127.0.0.1:9090/v1/server_info`):
- APISIX Dashboard version, if relevant:
- Plugin runner version, for issues related to plugin runners:
- LuaRocks version, for installation issues (run `luarocks --version`):