Nginx proxy loses connection to server or webapp containers after assigning new internal private IP because if one of these containers restarted, Docker automatically will assign a new IP address to it , the cached DNS resolution of nginx will not be able to connect to new container IP because the DNS resolution being done in server starting (so always reloading/restarting the nginx refreshes the DNS)
Nginx proxy loses connection to server or webapp containers after assigning new internal private IP because if one of these containers restarted, Docker automatically will assign a new IP address to it , the cached DNS resolution of nginx will not be able to connect to new container IP because the DNS resolution being done in server starting (so always reloading/restarting the nginx refreshes the DNS)