Failed to Send Email with alert manager

[Victor Massao]

I have prometheus that is sending alerts to alertmanager installed in the same machine but I dont receive any alerts through my email.

ts=2023-09-22T13:19:55.985Z caller=main.go:245 level=info msg="Starting Alertmanager" version="(version=0.26.0, branch=HEAD, revision=d7b4f0c7322e7151d6e3b1e31cbc15361e295d8d)"
ts=2023-09-22T13:19:55.985Z caller=main.go:246 level=info build_context="(go=go1.20.7, platform=linux/amd64, user=root@df8d7debeef4, date=20230824-11:11:58, tags=netgo)"
ts=2023-09-22T13:19:55.988Z caller=cluster.go:186 level=info component=cluster msg="setting advertise address explicitly" addr=172.18.69.90 port=9094
ts=2023-09-22T13:19:55.991Z caller=cluster.go:683 level=info component=cluster msg="Waiting for gossip to settle..." interval=2s
ts=2023-09-22T13:19:56.022Z caller=coordinator.go:113 level=info component=configuration msg="Loading configuration file" file=/etc/alertmanager/alertmanager.yml
ts=2023-09-22T13:19:56.022Z caller=coordinator.go:126 level=info component=configuration msg="Completed loading of configuration file" file=/etc/alertmanager/alertmanager.yml
ts=2023-09-22T13:19:56.024Z caller=tls_config.go:274 level=info msg="Listening on" address=[::]:9093
ts=2023-09-22T13:19:56.024Z caller=tls_config.go:277 level=info msg="TLS is disabled." http2=false address=[::]:9093
ts=2023-09-22T13:19:57.992Z caller=cluster.go:708 level=info component=cluster msg="gossip not settled" polls=0 before=0 now=1 elapsed=2.000809726s
ts=2023-09-22T13:20:05.994Z caller=cluster.go:700 level=info component=cluster msg="gossip settled; proceeding" elapsed=10.00349529s
ts=2023-09-22T13:20:30.557Z caller=notify.go:745 level=warn component=dispatcher receiver=email integration=email[0] aggrGroup="{}:{alertname=\"InstanceDown\"}" msg="Notify attempt failed, will retry later" attempts=1 err="create SMTP client: EOF"


Above is what the logs write

Below is my alertmanager.service file


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

[Service]
User=alertmanager
Group=alertmanager
Type=simple
ExecStart=/usr/local/bin/alertmanager \
    --cluster.listen-address= \
    --config.file /etc/alertmanager/alertmanager.yml \
    --storage.path /var/lib/alertmanager/

[Install]
WantedBy=multi-user.target

Any help please??

[Brian Candler]

err="create SMTP client: EOF" means you have a problem with how you've configured communication with your SMTP server.

That will be configured in your alertmanager.yml config file, in the email_configs and/or global sections (not in alertmanager.service)