A couple of things:
- Ensure that the AP's MGMT vlan is set as native on the port
- look at the connected clients on the port to see if the AP has an IP address.
- try connecting to the AP's local status page to verify it's current state
https://documentation.meraki.com/General_Administration/Tools_and_Troubleshooting/Using_the_Cisco_Me...
Finally, I have encountered occasional s where despite the network being setup and the AP pulling config and being solid green or blue LED, it continues to show as never connected in the dashboard. In those scenarios a combo of factory reset and deleting and re-adding to network usually resolved the issue.