Troubleshooting Tip: FortiAP-224E loses connection to the FortiGate after upgrading to v7.4.2

[ehamud]

Description	This article describes how to resolve an issue where the FAP221E loses connection to the FortiGate after upgrading to FortiOS v7.4.2.
Scope	FAP-221E using any firmware version, connected to FortiGate with v7.4.2.
Solution	The 221E models - including Gen1, Gen2, Gen3 - sometimes do not show with the online state when the FortiGate is upgraded to v7.4.2. See below for an example of the reply received by a diagnose command on the FortiGate when this error occurs. Here, the FortiGate shows the error 'reason 8 -- Control message maximal retransmission limit reached': diagnose wireless-controller wlac -c wtp -------------------------------WTP 1---------------------------- WTP vd : root, 0-FP221ETF18091550 MP00 uuid : b08c66c6-ae8d-51ee-cc38-da14b28a3549 mgmt_vlanid : 0 region code : C invalid refcnt : 2 own(1) wtpprof(1) deleted(no) apcfg status : N/A,N/A cfg_ac=0.0.0.0:0 val_ac=0.0.0.0:0 cmds T 0 P 0 U 0 I 0 M 0 apcfg cmd details: plain_ctl : disabled image-dl(wtp,rst): yes,no admin : enable wtp-profile : cfg(fap221ecn) override(disabled) oper(fap221ecn) wtp-mode : normal wtp-wanlan-mode : wan-only cfg-apcfg-prof : oper-apcfg-pro : bonjour-profile : wtp-group : name : location : region-map : pos-x : 0 pos-y : 0 ble-major-id : 0 (wtp: 0, grp: 0, prof: 0) ble-minor-id : 0 (wtp: 0, prof: 0) led-blink : disabled led-state : enabled led-schedules : poe mode : auto(auto) poe-mode-oper : auto ext-info-enable : enabled ip-frag-prevent : TCP_MSS tun-mtu : 0,0 split-tunneling-acl-path : local split-tunneling-local-ap-subnet : disabled active sw ver : FP221E-v7.2-build0337 local IPv4 addr : 192.168.10.3 board mac : e8:1c:ba:43:a7:00 join_time : Sat Jan 13 09:15:47 2024 mesh-uplink : ethernet mesh hop count : 0 parent wtp id : connection state : Disconnected (0-0.0.0.0:0) image download progress: 0 (upd-init,1128159 hold 0 rst 0) last failure : 8 -- Control message maximal retransmission limit reached last failure param: N/A last failure time: Wed Jan 17 12:21:54 2024 station info : 0/0 geo : World (0) deployment : cfg platform-determined oper indoor The issue is triggered by a FortiOS timezone change in 7.4.2. A workaround is to reboot the FAP221E, but the final solution is to install FAP_221E-v700-build4156-FORTINET under the FortiAP. Open a ticket with Fortinet TAC support to get this version. After installing it, the FAP221E model will be able to go online without any interruption. One extra step always validates the FortiOS vs FortiAP compatibility table, an exception may occur with FortiOS v7.4.2: FortiAP-W2 - FortiAP and FortiOS compatibility matrix. Additionally, consider the ideal FortiAP upgrade path before upgrading FortiAP directly to the final desired version to avoid unexpected behavior.