Alertmanager Silenced alerts appearing in alerts tab

[rwywawn]

After spinning up the alertmanager with minimal configs and sending an alert with postman, silencing the alert in the ui doesn't remove the alert from the alerts tab. It does exist in the silences tab.

# alertmanager-config.yml
multitenancy_enabled: false 
alertmanager:
  sharding_ring:
    replication_factor: 1  
  persist_interval: 15s

alertmanager_storage:
  backend: filesystem  
  filesystem:
    dir: /tmp/alertmanager-data  

server:
  http_listen_port: 8080  
  log_level: debug  

# fallback_config_file
route:
  group_by: ['alertname']
  group_wait: 30s
  group_interval: 5m
  repeat_interval: 1h
  receiver: 'web.hook'
receivers:
  - name: 'web.hook'
    webhook_configs:
      # - url: 'http://127.0.0.1:5001/'
inhibit_rules:
  - source_match:
      severity: 'critical'
    target_match:
      severity: 'warning'
    equal: ['alertname', 'dev', 'instance']

I run this command

./mimir-darwin-arm64 -target=alertmanager -config.file=alertmanager-config.yml

Then once its running I make this post request to http://localhost:8080/alertmanager/api/v2/alerts with this body

[
   {
       "labels": {
           "alertname": "TestAlert",
           "severity": "critical"
       },
       "annotations": {
           "summary": "This is a test alert",
           "description": "Testing silencing and routing"
       },
       "startsAt": "2025-08-01T13:59:29-07:00"
   }
]

Here is the alert

and here is the silence

Now when I go back into the alerts tab, the alert is still there even though it should be silenced.

Looking at the logs, this is the only error message I see.

ts=2025-08-04T20:03:50.256334Z caller=dispatch.go:390 level=error component=MultiTenantAlertmanager user=anonymous component=dispatcher insight=true component=dispatcher msg="Notify for alerts failed" num_alerts=1 err="invalid service state: Terminated, expected: Running"

Any Idea why this could be happening? Am I missing some configuration?