# Description of DISCOURSE\_SMTP\_\* fields
**URL:** https://meta.discourse.org/t/description-of-discourse-smtp--fields/43498
**Category:** Self-hosting
**Created:** [30 Aprile 2016, 11:36am UTC](https://meta.discourse.org/t/description-of-discourse-smtp--fields/43498 "2016-04-30T11:36:04Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@Benninger](https://meta.discourse.org/u/Benninger)
#### Post date: [30 Aprile 2016, 11:36am UTC](https://meta.discourse.org/t/description-of-discourse-smtp--fields/43498/1 "2016-04-30T11:36:05Z")
I am getting the error
> Job exception: 504 PLAIN authentication is not permitted by this server.
Where are the DISCOURSE\_SMTP\_\* parameters explained and which one do I have to change?
---
### Author:  [@codinghorror](https://meta.discourse.org/u/codinghorror)
#### Post date: [30 Aprile 2016, 11:39am UTC](https://meta.discourse.org/t/description-of-discourse-smtp--fields/43498/2 "2016-04-30T11:39:38Z")
Read the `app.yml` file – it’s right in there. Search for “SMTP” in your editor of choice.
---
### Author:  [@Benninger](https://meta.discourse.org/u/Benninger)
#### Post date: [30 Aprile 2016, 11:53am UTC](https://meta.discourse.org/t/description-of-discourse-smtp--fields/43498/3 "2016-04-30T11:53:45Z")
Ah, that are all available parameters, ok.
is DISCOURSE\_SMTP\_ENABLE\_START\_TLS: true the right one for my problem?
It is set to true
---
### Author:  [@Benninger](https://meta.discourse.org/u/Benninger)
#### Post date: [30 Aprile 2016, 12:22pm UTC](https://meta.discourse.org/t/description-of-discourse-smtp--fields/43498/4 "2016-04-30T12:22:15Z")
Ok, ty for your help - i switched to mailgun and everything is fine - I will check my problems in the next few days.