Alerts are not displaying in the Alertmanager UI and I'm not getting notified on my email client i.e., outlook despite they're in firing state

Question

Image of alerts that are in firing state Image of alerts not kicking in the alert manager UI despite they are firing What else do I need to refactor in the alertmanager.yml to get notified on outlook. I'm not running this setup on top of conatiners, I installed node-exporter, prometheus and alertmanager individually Alertmanager.yml

global:
  smtp_smarthost: 'smtp.office365.com:587'
  smtp_from: '[email protected]'
  smtp_auth_username: '[email protected]'
  smtp_auth_password: 'secret'

route:
  repeat_interval: 1m
  receiver: team-X-mails
receivers:
- name: 'team-X-mails'
  email_configs:
  - to: '[email protected]'

prometheus.yml

global:
  scrape_interval:     15s # Set the scrape interval to every 15 seconds. Default is every 1 minute.
  evaluation_interval: 15s # Evaluate rules every 15 seconds. The default is every 1 minute.



alerting:
  alertmanagers:
    - scheme: http
      static_configs:
        - targets: ['localhost:9093']

rule_files:
   - "prometheus.rules.yml"
   - "alerting.rules.yml"
scrape_configs:
  - job_name: 'prometheus'

    static_configs:
    - targets: ['localhost:9090']

  - job_name: 'prometheus_master'
    file_sd_configs:
    - files: ['targets/*.yml']
      refresh_interval: 30s

alerting-rules.yml

groups:
- name: server_is_down
  rules:
  - alert: InstanceDown
    expr: up == 0
    for: 1m
    labels:
      severity: critical
    annotations:
      summary: "Instance - {{ $labels.instance }} is down"
      description: "This is the instance - {{ $labels.instance }} of job {{ $labels.job }} has been down."

- name: cpu_utilized
  rules:
  - alert: HighCPUUsage
    expr: 100 - (avg by (instance) (irate(node_cpu_seconds_total{job="prometheus_master",mode="idle"}[5m])) * 100) > 80

    labels:
      severity: critical
    annotations:
      summary: "High CPU Usage on this instance - {{ $labels.instance }}"
      description: "CPU usage on this instance - {{ $labels.instance }} is above 80%"

- name: memory_utilized
  rules:
  - alert: HighMemoryUsage
    expr: 100 * (1 - ((node_memory_MemAvailable_bytes) / (node_memory_MemTotal_bytes))) > 50

    labels:
      severity: critical
    annotations:
      summary: "High Memory Usage on this instance - {{ $labels.instance }}"
      description: "Memory usage on this instance - {{ $labels.instance }} is above 50%"

- name: disk_utilized_scratch_tmp
  rules:
  - alert: DiskSpaceExhausted
    expr: ((node_filesystem_size_bytes{mountpoint="/scratch"} - node_filesystem_free_bytes{mountpoint="/scratch"}) / node_filesystem_size_bytes{mountpoint="/scratch"} * 100 > 80) or ((node_filesystem_size_bytes{mountpoint="/tmp"} - node_filesystem_free_bytes{mountpoint="/tmp"}) / node_filesystem_size_bytes{mountpoint="/tmp"} * 100 > 80)
 
    labels:
      severity: critical
    annotations:
      summary: "Disk Space Exhausted on this instance - {{ $labels.instance }}"
      description: "Disk space utilized on this instance - {{ $labels.instance }} is above 90%"

prometheus.service

[Unit]
Description=Prometheus
Wants=network-online.target
After=network-online.target

[Service]
User=prometheus
Group=prometheus
Type=simple
ExecStart=/usr/local/bin/prometheus \
--config.file /etc/prometheus/prometheus.yml \
--storage.tsdb.path /var/lib/prometheus_data \
--web.console.templates=/etc/prometheus/consoles \
--web.console.libraries=/etc/prometheus/console_libraries \
--web.external-url=http://hostname


[Install]
WantedBy=multi-user.target

alertmanger.service

[Unit]
Description=Alertmanager
Wants=network-online.target
After=network-online.target

[Service]
User=alertmanager
Group=alertmanager
Type=simple
WorkingDirectory=/etc/alertmanager/
ExecStart=/usr/local/bin/alertmanager --config.file=/etc/alertmanager/alertmanager.yml --web.external-url=http://hostname:9093

[Install]
WantedBy=multi-user.target