The EMQX 4.4.19 memory increases rapidly

Recently, a situation suddenly occurred in my EMQX. I have thousands of devices to connect to my EMQX, but my CPU and Memory will explode within a few hours, reaching the situation shown in the picture below, causing my EMQX to lose its function. Someone Has this ever happened? I’m Ubuntu: 18.04.6 Emqx:4.4.19, thank you for your help