# CHAP/PAP authentication over LTE
**URL:** https://forum.legato.io/t/chap-pap-authentication-over-lte/6624
**Category:** Legato Application Framework
**Created:** [November 9, 2023, 6:21pm UTC](https://forum.legato.io/t/chap-pap-authentication-over-lte/6624 "2023-11-09T18:21:08Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@sergio.farias](https://forum.legato.io/u/sergio.farias)
#### Post date: [November 9, 2023, 6:21pm UTC](https://forum.legato.io/t/chap-pap-authentication-over-lte/6624/1 "2023-11-09T18:21:08Z")
Hi,
I need to use the chap/pap authentication over LTE. I’m developing a firmware using the legato API. The functions used are: **le\_mdc\_SetAuthentication** to authentication and le\_mdc\_StartSession to start data connection. When the technology is LTE the data connection fails with LE\_FAULT return code, but with UMTS technology the data connection is Ok. Is it possible to make it works with LTE?
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### Author:  [@jyijyi](https://forum.legato.io/u/jyijyi)
#### Post date: [November 10, 2023, 12:56am UTC](https://forum.legato.io/t/chap-pap-authentication-over-lte/6624/2 "2023-11-10T00:56:18Z")
did you try with “cm data auth …” command first?
> **[cm - Legato Docs](https://docs.legato.io/latest/toolsTarget_cm.html)**
>
> legato™ is an open source Linux-based embedded platform designed to simplify connected IoT application development
You can also try to use at!QCPDPP command and the method here:
> **[WP7502 not connecting to LTE private APN](https://forum.sierrawireless.com/t/wp7502-not-connecting-to-lte-private-apn/16042/5)**
>
> maybe you can try this command:
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### Author:  [@sergio.farias](https://forum.legato.io/u/sergio.farias)
#### Post date: [November 10, 2023, 2:52pm UTC](https://forum.legato.io/t/chap-pap-authentication-over-lte/6624/3 "2023-11-10T14:52:08Z")
Hi jyijyi,
Thank you for your reply!
The at!QCPDPP command worked fine!