追加したAP（AIR-AP18321-Q-K9C）がWLCに帰属できず、Imageをダウンロードしてくるところで下記ログのようになり、リトライが繰り返されてしまいます。
WLC側のソフトウェアバージョンが8.4.100.0で追加APが8.5.105.0ですが、このバージョン不一致が原因でしょうか。
また、8.5.105.0にアップデートした場合は、Configの再設定が必要となるのでしょうか。
・ログ抜粋
[*05/07/2018 22:43:04.0000] CAPWAP State: DTLS Setup
[*05/07/2018 22:43:04.0699]
[*05/07/2018 22:43:04.0699] CAPWAP State: Join
[*05/07/2018 22:43:04.0699] Sending Join request to 172.16.6.19 through port 5272
[*05/07/2018 22:43:04.0799] Join Response from 172.16.6.19
[*05/07/2018 22:43:04.1799]
[*05/07/2018 22:43:04.1799] CAPWAP State: Image Data
[*05/07/2018 22:43:04.2399] do PRECHECK, part1 is active part
[*05/07/2018 22:43:04.2799] Image Data Request sent to 172.16.6.19
[*05/07/2018 22:43:04.2799] AC rejected join request[17], try again later.
[*05/07/2018 22:43:04.2799]
[*05/07/2018 22:43:04.2799] Controller rejected image download.Check if TFTP server configured on ME WLC or maximum concurrent download limit has reached
[*05/07/2018 22:43:20.2249] Discarding msg CAPWAP_WTP_EVENT_REQUEST(type 9) in CAPWAP state: Image Data(10).
