# Heartbeat - monitor email domains
**URL:** https://discuss.elastic.co/t/heartbeat-monitor-email-domains/341306
**Category:** Synthetics
**Created:** [August 21, 2023, 10:08pm UTC](https://discuss.elastic.co/t/heartbeat-monitor-email-domains/341306 "2023-08-21T22:08:38Z")
**Posts on this page:** 6
**Page:** 1
### Author:  [@Robin020](https://discuss.elastic.co/u/Robin020)
#### Post date: [August 21, 2023, 10:08pm UTC](https://discuss.elastic.co/t/heartbeat-monitor-email-domains/341306/1 "2023-08-21T22:08:38Z")
Hello,
I am trying to monitor email domains (with heartbeat) for example:
```auto
- type: tcp
name: TLS_CHECK
schedule: '@every 30s'
hosts: ["tls://mx.example.com"]
ports: [25]
```
Unfortantly this give me the following error:
`tls: first record does not look like a TLS handshake`
What's going wrong?
When removing the scheme before the host, it works but I don't get the tls certificate which my goal is to monitor.
Hope somebody have suggestions to solve this.
---
### Author:  [@Rios](https://discuss.elastic.co/u/Rios)
#### Post date: [August 22, 2023, 6:49am UTC](https://discuss.elastic.co/t/heartbeat-monitor-email-domains/341306/2 "2023-08-22T06:49:54Z")
If you want to use SSL session, there should be a certificate.
```auto
ssl:
certificate_authorities: ['/etc/ca.crt']
```
Check [the documentation](https://www.elastic.co/guide/en/beats/heartbeat/current/monitor-tcp-options.html#monitor-tcp-tls-ssl)
---
### Author:  [@Robin020](https://discuss.elastic.co/u/Robin020)
#### Post date: [August 22, 2023, 10:40am UTC](https://discuss.elastic.co/t/heartbeat-monitor-email-domains/341306/3 "2023-08-22T10:40:36Z")
Still get the same error. This is the config:
```auto
- type: tcp
name: TLS_CHECK
schedule: '@every 30s'
hosts: ["smtp.google.com"]
ports: [25]
ssl:
certificate_authorities: ['/etc/heartbeat/ca.crt']
supported_protocols: ["TLSv1.1", "TLSv1.2"]
```
I have used the ca.crt from the elasticsearch folder (/etc/elasticsearch/certs/http\_ca.crt).
What I am doing wrong here?
---
### Author:  [@emilioalvap](https://discuss.elastic.co/u/emilioalvap)
#### Post date: [August 22, 2023, 3:13pm UTC](https://discuss.elastic.co/t/heartbeat-monitor-email-domains/341306/4 "2023-08-22T15:13:20Z")
Hi @Robin020,
`STMP:25` is not a TLS-by-default service, although it can accept TLS negotiation post-fact. Since heartbeat is expecting to get a TLS negotiation handshake, it shows that error when the remote party does not continue with the flow.
You'll need to figure out of your service provides a TLS-secured version on a different port.
---
### Author:  [@Rios](https://discuss.elastic.co/u/Rios)
#### Post date: [August 22, 2023, 6:50pm UTC](https://discuss.elastic.co/t/heartbeat-monitor-email-domains/341306/5 "2023-08-22T18:50:44Z")
Good catch Emilio. Standard ports:
- (Gmail) SMTP port (TLS): 587
- (Gmail) SMTP port (SSL): 465
---
### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [September 19, 2023, 6:51pm UTC](https://discuss.elastic.co/t/heartbeat-monitor-email-domains/341306/6 "2023-09-19T18:51:06Z")
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