Wi-Fi stoppage when iPad connected to macbook

I used 11” iPad Pro 2018 to connect 15” MacBook Pro 2018. I can use the program without problem when “opening” the screen of the MacBook. (Normal use) However, I can still use the iPad to control my MacBook (in the same room Wi-Fi connection) when closing the screen (jump desktop connected before closing the screen). But Wi-Fi stoppage issue appears for every 20-30 seconds. And the connection will be back for a while. (For example: in YouTube, there will be black screen every 20-30s) What happens?