Authentication issue

Hello Everyone,

1- I am currently experiencing an issue with my FortiGate 500E, running software version 6.4.7. The problem arises intermittently when some users connect to the wireless network, resulting in a complete loss of internet connectivity.

2- Upon reviewing the firewall logs, I observed that affected users are marked as de-authenticated, denoted by an orange user icon, as shown in the attached screenshot.

3- also upon Collector agent Logs, I found that the affected users are not shown as well in the logon users tap in the collector

4- as a workaround to resolve this issue, users are asked to sign out and sign in multiple times, or in some cases, they need to restart their laptops. I am reaching out to seek guidance on addressing this issue and to inquire if others have encountered a similar situation.