For more information on Grafana's SMTP configuration see Grafana's [documentation](https://grafana.com/docs/grafana/latest/administration/configuration/#smtp).
## Troubleshooting
### X.509: certificate signed by unknown authority
When using a self-signed SSL certificate for GitLab, you may get the following error in the UI:
```plaintext
login.OAuthLogin(NewTransportWithCode)
Check the Grafana server logs for the detailed error message.
```
The error reported in the Grafana logs at `/var/log/gitlab/grafana/current` can be:
```plaintext
lvl=eror msg=login.OAuthLogin(NewTransportWithCode) logger=context userId=0 orgId=0 uname= error="Post \"https://gitlab.example.com/oauth/token\": x509: certificate signed by unknown authority"
```
In this case, you must [install the self-signed GitLab certificate as trusted](ssl.md#install-custom-public-certificates).