| Code | 802.11 definition | Explanation |
| 0 | Reserved | Normal working operation |
| 1 | Unspecified reason | We don’t know what’s wrong |
| 2 | Previous authentication no longer valid | Client has associated but is not authorised. |
| 3 | station is leaving (or has left) IBSS or ESS | The access point went offline, deauthenticating the client. |
| 4 | Disassociated due to inactivity | Client session timeout exceeded. |
| 5 | Disassociated because AP is unable to handle all currently associated stations | The access point is busy, performing load balancing, for example. |
| 6 | Class 2 frame received from nonauthenticated station | Client attempted to transfer data before it was authenticated. |
| 7 | Class 3 frame received from nonassociated station | Client attempted to transfer data before it was associated. |
| 8 | Disassociated because sending station is leaving (or has left) BSS | Operating System moved the client to another access point using non-aggressive load balancing. |
| 9 | Station requesting (re)association is not authenticated with responding station | Client not authorized yet, still attempting to associate with an access poin |
| 10 | Disassociated because the information in the Power Capability element is unacceptable | |
| 11 | Disassociated because the information in the Supported Channels element is unacceptable | |
| 12 | Reserved | Not Used or Special Purpose |
| 13 | Invalid information element, i.e., an information element defined in this standard for | |
| which the content does not meet the specifications in Clause 7 | ||
| 14 | Message integrity code (MIC) failure | |
| 15 | 4-Way Handshake timeout | |
| 16 | Group Key Handshake timeout | |
| 17 | Information element in 4-Way Handshake different from (Re)Association Request/Probe | |
| Response/Beacon frame | ||
| 18 | Invalid group cipher | The link speed requested by the client or AP is incompatible. (i,e. trying to operate N only speeds on a G AP) |
| 19 | Invalid pairwise cipher | |
| 20 | Invalid AKMP | |
| 21 | Unsupported RSN information element version | |
| 22 | Invalid RSN information element capabilities | |
| 23 | IEEE 802.1X authentication failed | |
| 24 | Cipher suite rejected because of the security policy | |
| 25-31 | Reserved | |
| 32 | Disassociated for unspecified, QoS-related reason | Quality of Service has denied the action |
| 33 | Disassociated because QAP lacks sufficient bandwidth for this QSTA | |
| 34 | Disassociated because excessive number of frames need to be acknowledged, but are not | |
| acknowledged due to AP transmissions and/or poor channel conditions | ||
| 35 | Disassociated because QSTA is transmitting outside the limits of its TXOPs | |
| 36 | Requested from peer QSTA as the QSTA is leaving the QBSS (or resetting) | |
| 37 | Requested from peer QSTA as it does not want to use the mechanism | |
| 38 | Requested from peer QSTA as the QSTA received frames using the mechanism for which | |
| a setup is required | ||
| 39 | Requested from peer QSTA due to timeout | |
| 40 | Peer QSTA does not support the requested cipher suite | |
| 46-65535 | 46--65 535 Reserved |
https://support.zyxel.eu/hc/en-us/articles/360009469759-What-is-the-meaning-of-802-11-Deauthentication-Reason-Codes-