The first time access to the nginx deployment website interface is 503, you need to request the second time to get the data.

The project deployed by Java uses Nginx as a proxy to forward
and find that the front end will request twice when requesting the interface to obtain data. The first time the interface reports error 503 as shown in the figure below, and the second time can normally obtain the data

. Modify the concurrency limit of Nginx.
Find the limit_conn perip parameter in the server configuration and increase the value appropriately. Restart
Nginx.

// 单个IP并发数限制
server{
    
    
    limit_conn perip 20;
    limit_conn perserver 20;
}