Wireless connection fails occasional

I have a wireless connection between an AR150 (Master) and an AR300 (Client). Both run on OpenWrt 22.03.5, 24/7 operation. The connection is fairly stable, but occasional fails and does not come up on its own. I have to reboot the master in this case. The connection will come up after the reboot and stay online some weeks again.

What can I do to track down the cause of the failure, and/or make the connection more stable?