# Error on API Tester
**URL:** https://forum.mautic.org/t/error-on-api-tester/6667
**Category:** Product Support
**Created:** [November 25, 2016, 3:19pm UTC](https://forum.mautic.org/t/error-on-api-tester/6667 "2016-11-25T15:19:11Z")
**Posts on this page:** 2
**Page:** 1
### Author:  [@denismc2](https://forum.mautic.org/u/denismc2)
#### Post date: [November 25, 2016, 3:19pm UTC](https://forum.mautic.org/t/error-on-api-tester/6667/1 "2016-11-25T15:19:11Z")
I have a server with Mautic and I want to use the REST API without browser confirmation. So I download the API Tester from [https://github.com/mautic/api-library/archive/master.zip](https://github.com/mautic/api-library/archive/master.zip) to generate an OAuth1a access token that never expires.
When I press the Authorize button the follow error shows up:
Fatal error: Uncaught Error: Class ‘MauticAuthApiAuth’ not found in /home/u210360206/public\_html/apitester/index.php:142 Stack trace: #0 {main} thrown in /home/u210360206/public\_html/apitester/index.php on line 142
How can I solve this?
Tks
---
### Author:  [@denismc2](https://forum.mautic.org/u/denismc2)
#### Post date: [November 25, 2016, 3:19pm UTC](https://forum.mautic.org/t/error-on-api-tester/6667/2 "2016-11-25T15:19:11Z")
I have a server with Mautic and I want to use the REST API without browser confirmation. So I download the API Tester from [https://github.com/mautic/api-library/archive/master.zip](https://github.com/mautic/api-library/archive/master.zip) to generate an OAuth1a access token that never expires.
When I press the Authorize button the follow error shows up:
Fatal error: Uncaught Error: Class ‘MauticAuthApiAuth’ not found in /home/u210360206/public\_html/apitester/index.php:142 Stack trace: #0 {main} thrown in /home/u210360206/public\_html/apitester/index.php on line 142
How can I solve this?
Tks