Disable class C support

Hello, I have wrongly enabled the class C capability when I declared my device (OTAA). As a result, any attempt to downlink a message fails. I have unchecked the Class C setting through the TTN console and by the CLI, but downlink messages are still sent by TTN as if it was a class C device. What can I do to properly downlink a message to my device ?
Many thanks for your answer.

You need to restart the device to reset the state in TTN. (Or try to use ttncli command line tool to manipulate active configuration if possible)

Thanks for your answer. My device is difficult to reach (and to reset), so the reset is not really an option. What sort of CLI command should I use ?
Many thanks.

It is ages since I last used the cli, may-be @descartes can help out.
If you are in a hurry. There are commands to list the current setting and there should be a configuration tree and an operational tree, you need to set a value in the second one.