I'm not getting notified on my email client i.e., outlook despite they're in firing state

Question

Below is the configuration file for alertmanager to send emails when threshold is breached. In my case the alerts are firing but I'm not getting notified on my client outlook in my case. What should I do to get notified.

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