For me what happened is that when I upgraded the network to 31.1.5 the MR55, MR56 and CW9163Es all upgraded, but the CW9166I went into a bootloop where it was up for about a minute, a client could connect, but then it would crash and reboot. I did a factory reset on the CW9166I and this allowed it to boot, but it broadcast the Meraki SSID and could not connect to the cloud servers. The AP was replaced by RMA and the new one also bootlooped and never got the correct config. I downgraded to 31.1.4, but although all the other APs behaved, the CW9166I continued to bootloop. I downgraded to 30.7 and the same again. Having reported this all to support, the release was pulled and I am waiting for them to decide if I should do a factory reset or get another RMA replacement...
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