DFS is (Dynamic Frequency Selection) in 5GHz Wi-Fi frequencies that are generally reserved for radar, such as military radar, satellite communication, and weather radar. The DFS channels vary from country to country. The main benefit to use DFS channels in AP is to increase the number of Wi-Fi channels.
If the AP is already operating on DFS channel then it will monitor the current channel for radar signals continuously. If the AP detects any radar on the DFS channel, the AP will mute that channel (for a period of time) and will not pass client traffic or the client connection.
The log indicates the same that it is detecting the Radar signal on the channel and it is muting the channel.
You can select any NON-DFS channel or uncheck the DFS channel AP is using.