Various wifi disconnect codes, useful when debugging wifi disconnect issues
When troubleshooting WiFi networks, one of the most confusing things administrators encounter are WiFi de-authentication reason codes. These codes are generated when a client device disconnects from an access point (AP) and are part of the IEEE 802.11 wireless standard.
Unfortunately, the official documentation can be difficult to track down, and much of the information online is outdated or incomplete. This guide provides a complete list of reason codes with explanations to help you quickly understand what’s happening on your network.
What Are WiFi De-Authentication Reason Codes?
WiFi de-authentication reason codes are numeric values returned by an AP when a client is disconnected. Each code corresponds to a specific cause, such as inactivity, failed authentication, or insufficient resources.
These codes are critical for network engineers, IT admins, and support teams who need to debug connectivity issues. For example, knowing whether a disconnect happened due to inactivity or because the access point was overloaded can drastically change the troubleshooting approach.
Complete List of WiFi De-Authentication Reason Codes
| Code |
Reason |
Explanation |
| 0 | Reserved | Normal working operation |
| 1 | Unspecific Reason | The AP doesn’t know what went wrong |
| 2 | Previous authentication no longer valid | Client has associated but is no longer authorized |
| 3 | STA leaving IBSS/ESS | The access point went offline, disconnecting the client |
| 4 | Disassociated due to inactivity | Client session timeout exceeded |
| 5 | AP cannot handle more clients | The access point is overloaded or load balancing |
| 6 | Class 2 frame from nonauthenticated STA | Client tried sending data before authentication |
| 7 | Class 3 frame from nonassociated STA | Client tried sending data before association |
| 8 | STA leaving BSS | OS moved the client to another AP (non-aggressive load balancing) |
| 9 | STA not authenticated | Client attempted association before authorization |
| 10 | Power Capability unacceptable | Client device power element mismatch |
| 11 | Supported Channels unacceptable | Client channel request not supported |
| 12 | Reserved | Not used |
| 13 | Invalid information element | Invalid frame data received |
| 14 | MIC failure | Message integrity check failed |
| 15 | 4-Way Handshake timeout | Client/AP failed WPA2 handshake |
| 16 | Group Key Handshake timeout | Group key negotiation failed |
| 17 | Handshake info mismatch | Key information inconsistent across frames |
| 18 | Invalid group cipher / unsupported data rates | AP/client requested incompatible speeds |
| 19 | Invalid pairwise cipher | Client/AP cipher mismatch |
| 20 | Invalid AKMP | Invalid authentication and key management |
| 21 | Unsupported RSN version | Security protocol mismatch |
| 22 | Invalid RSN capabilities | AP and client capability mismatch |
| 23 | IEEE 802.1X authentication failed | Client authentication failed via RADIUS/802.1X |
| 24 | Cipher suite rejected | Blocked by AP’s security policy |
| 25–31 | Reserved | Not used |
| 32 | QoS-related unspecified | Quality of Service denied the action |
| 33 | QoS insufficient bandwidth | AP lacks bandwidth for QoS STA |
| 34 | Excessive unacknowledged frames | Poor channel conditions caused drop |
| 35 | TXOP limits exceeded | STA transmitted outside permitted time slots |
| 36 | Requested by peer STA | STA left BSS (reset or disconnect) |
| 37 | Peer STA does not want mechanism | Requested disconnect by peer |
| 38 | Peer STA received frame without setup | Incorrectly configured frame exchange |
| 39 | Peer STA timeout | Timeout caused disconnect |
| 45 | Unsupported cipher suite | Peer STA does not support the requested cipher |
| 45–65 | Reserved | Not used |
| 99 | No Reason Code | Unknown state, generic disconnect |
| 535 | Reserved | Not used |
Why These Codes Matter
Knowing the specific reason code behind a WiFi disconnect allows you to:
- Troubleshoot faster - immediately identify whether the issue is authentication, load, or security related.
- Improve user experience - by diagnosing recurring disconnects and fixing root causes.
- Optimize networks - especially in enterprise or hospitality environments where guest WiFi stability is critical.
For example:
- If you see many Code 4 (inactivity) disconnects, you may need to adjust session timeouts.
- If Code 5 (AP overloaded) occurs often, you may need load balancing or more access points.
- Handshake failures (Codes 15–17) usually point to WPA2/WPA3 configuration issues.
For a complete setup walkthrough, check out our BIG GUIDE to setting up Spotipo hotspots with UniFi devices (NEW UI).
