Why are regex URLs specified in Ory Oathkeeper's access rules not being matched?

Question

I have been using Ory Oathkeeper for a little while, about 2 months ago I had everything working, but now since taking a break and coming back, nothing seems to be working correctly.

I have 3 files, oathkeeper.yml,kratos.json and rules.json. The oathkeeper config has both the kratos and rules files specified correctly, the rule specified in kratos.json appears to work correctly, but what's bizarre is that the access rule specified in rules.json doesn't work at all. I have confirmed that the access rules for both are being picked up by oatheeper using the CLI command oathkeeper rules list.

This leads me to believe that the issue isn't with the rules themselves but with the regex. However, posting the regex rule to an online regex tester like regexr shows me that it works correctly. My guess is maybe the .go library used by Oathkeeper could be broken somehow, or that maybe I am doing something wrong in the JSON.

Below are my rules:

// kratos.json
[
  {
    "id": "ory:kratos:public",
    "upstream": {
      "preserve_host": true,
      "url": "http://kratos:4433",
      "strip_path": "/.ory/kratos/public"
    },
    "match": {
      "url": "<(http|https):\\/\\/([\\w-]+(\\.[\\w-]+)*|[\\d.]+)(:\\d+)?\\/\\.ory\\/kratos\\/public(\\/.*)?>",
      "methods": ["GET", "POST" ,"PUT", "DELETE", "PATCH"]
    },
    "authenticators": [{
      "handler": "noop"
    }],
    "authorizer": {
      "handler": "allow"
    },
    "mutators": [{
      "handler": "noop"
    }]
  }
]

// rules.json
[
  {
    "id": "fusion:account:protected",
    "upstream": {
      "preserve_host": true,
      "url": "http://host.docker.internal:80",
      "strip_path": "/api/account"
    },
    "match": {
      "url": "<(http|https):\\/\\/([\\w-]+(\\.[\\w-]+)*|[\\d.]+)(:\\d+)?\\/api\\/account(\\/.*)?>",
      "methods": ["GET", "POST" ,"PUT", "DELETE", "PATCH"]
    },
    "authenticators": [{
      "handler": "cookie_session"
    }, {
      "handler": "oauth2_introspection"
    }, {
      "handler": "anonymous"
    }],
    "authorizer": {
      "handler": "allow"
    },
    "mutators": [{
      "handler": "id_token"
    }],
    "errors": [{
      "handler": "json"
    }]
  }
]

// oathkeeper.yml
serve:
  proxy:
    port: 4455 # run the proxy at port 4455
  api:
    port: 4456 # run the api at port 4456

access_rules:
  matching_strategy: regexp
  repositories:
    - file:///etc/config/oathkeeper/rules.json
    - file:///etc/config/oathkeeper/kratos.json

log:
  level: debug
  format: text
  leak_sensitive_values: true

errors:
  fallback:
    - json
  handlers:
    json:
      enabled: true
      config:
        verbose: true
    redirect:
      enabled: true
      config:
        to: https://www.ory.sh/docs

mutators:
  header:
    enabled: true
    config:
      headers:
        X-User: "{{ print .Subject }}"
  noop:
    enabled: true
  id_token:
    enabled: true
    config:
      issuer_url: http://localhost:4455/
      jwks_url: file:///etc/config/oathkeeper/jwks.json
      claims: '{"scope":"{{ .Extra.scope }}"}'

authorizers:
  allow:
    enabled: true
  deny:
    enabled: true
  remote_json:
    # remote_json documentation: https://www.ory.sh/oathkeeper/docs/pipeline/authz#remote_json
    enabled: true
    config:
      remote: http://keto:4466/check
      # must be set explicitly, otherwise: https://github.com/ory/oathkeeper/issues/797
      forward_response_headers_to_upstream: []
      payload: |
        {
            "namespace": "...",
            "subject": "...",
            "object": "...",
            "relation": "..."
        }

authenticators:
  noop:
    enabled: true
  cookie_session:
    enabled: true
    config:
      check_session_url: http://kratos:4433/sessions/whoami
      preserve_path: true
      extra_from: "@this"
      subject_from: "identity.id"
      only:
        - ory_kratos_session
  anonymous:
    enabled: true
    config:
      subject: guest
  oauth2_introspection:
    enabled: true
    config:
      introspection_url: http://hydra:4445/oauth2/introspect

I have tried to hardcode URLs into the config, but they don't appear to work either. If I use something like http://localhost:4455/test and I go to this URL in my browser, I get the same error.

The error response I get is provided below:

{
  "error": {
    "code": 404,
    "status": "Not Found",
    "message": "Requested url does not match any rules"
  }
}