My Mac suddenly disconnects to WiFi

You need to setup security on your Router, Modem, or Hotspot, which exact one do yo have?

As there is very little usable Technical Information to work from.

Below is a best guess

1 - Restart the Router

2 - Refer to next link from Apple Suggested on suggested Wifi Setting Recommended settings for Wi-Fi routers and access points - Apple Support

Please solve this’s problem

mac WiFi network unsecured

3850AmberJack wrote:

Mac disconnects and then reconnects all the time

Please provide some problem details and context.

Writing an effective Apple Support Commun… - Apple Community