This article describes how to fix repetitive authentication failures that are seen on FortiNAC GUI.
FortiNAC 9.2.x and 9.4.x.
Under Logs -> Events & Alarms, repetitive authentication failures can be seen on FortiNAC GUI.
Users are authenticated via RADIUS doing MAC authentication or EAP-TLS (machine) and are getting network access without any issue.
| Date | Event | Element | Message |
| 11:40 | Authentication Failure | D4:54:8B:AA:88:33 | User host/pc-01 failed to log on IP address 192.168.50.11 |
| 11:40 | Authentication Failure | Alex_IPad | User B4-F6-1C-13-15-17 failed to log on IP address 192.168.60.11 |
This error can be checked by enabling the following debug:
> nacdebug -name DirectoryAuthentication true
yams.DirectoryAuthentication FINER :: 2022-12-19 10:51:19:773 :: #81 :: DirectoryAuthentication::getUserByUserID failed to find null trying other formats
yams.DirectoryAuthentication FINER :: 2022-12-19 10:51:19:774 :: #81 :: DirectoryAuthentication::loginHost getUserByUserID returning null
yams.DirectoryAuthentication FINER :: 2022-12-19 10:51:19:774 :: #81 :: DirectoryAuthentication::loginHost origClient IS null throw log on failure
This logs are not related to RADIUS authentication.
Example:
device -ip 10.0.0.1 -setAttr -name LoginUserFromForwardingData -value false
> device -ip 10.0.0.1
...
Name = LoginUserFormForwardingData value = false length = 5
The Fortinet Security Fabric brings together the concepts of convergence and consolidation to provide comprehensive cybersecurity protection for all users, devices, and applications and across all network edges.
Copyright 2026 Fortinet, Inc. All Rights Reserved.