Hi shlomoi,
In addition to rhbirkelund comment, the Cisco series 916x access points come pre-loaded with both DNA and Meraki images. This allows for flexibility in choosing which management mode will best suit you, the user. This document contains a pre-flight checklist for migrating APs from Meraki managed mode to DNA mode.
Do you have an IOS-XE controller?
The controller can be a physical 9800-CL or virtual vWLC in the cloud. DNA management mode APs cannot run in autonomous mode and require a controller to operate.
Please, find the documentation below - https://documentation.meraki.com/MR/Other_Topics/916X_Management_Mode_Checklist_and_Troubleshooting
If you found this post helpful, please give it kudos.
If my answer solved your problem, click "accept as solution" so that others can benefit from it.