Failing to connect to RCON serverdial

I'm using the following compose file:
```
version: '3.9'

services:
minecraft:
container_name: minecraft-atm7
image: itzg/minecraft-server:java17
ports:
- "25565:25565"
restart: unless-stopped
stdin_open: true
tty: true
environment:
EULA: "TRUE"
WORLD: /worlds/world
MEMORY: 16G
JVM_XX_OPTS: "-XX:+UseG1GC -XX:+ParallelRefProcEnabled -XX:MaxGCPauseMillis=200 -XX:+UnlockExperimentalVMOptions -XX:+DisableExplicitGC -XX:+AlwaysPreTouch -XX:G1NewSizePercent=40 -XX:G1MaxNewSizePercent=50 -XX:G1HeapRegionSize=32M -XX:G1ReservePercent=15 -XX:G1HeapWastePercent=5 -XX:G1MixedGCCountTarget=4 -X>
TYPE: FORGE
VERSION: 1.18.2
STOP_SERVER_ANNOUNCE_DELAY: 300
# Need to manually rev these (place downloaded pack in ./modpacks). This will be pulled in unless SKIP_GENERIC_PACK_UPDATE_CHECK: false is set here.
FORGEVERSION: 40.1.68
GENERIC_PACK: /modpacks/Server-Files-0.4.24.zip
# UUID ops here
OPS: 9d5101ef-4f07-431e-b86c-cc734e8a5952
# Server listing info
# config options
DIFFICULTY: normal
volumes:
# maps from host:container for data persistence
- ./data:/data
- ./modpacks:/modpacks:ro
- ./worlds:/worlds:ro
# Docker reservations
mem_limit: 25g
mem_reservation: 18g
# cpus: 0.5
backups:
container_name: backup-atm7
image: itzg/mc-backup
environment:
SERVER_PORT: 25565
# timing
BACKUP_INTERVAL: "1h"
INITIAL_DELAY: "2m"
# online player
PAUSE_IF_NO_PLAYERS: "true"
PLAYERS_ONLINE_CHECK_INTERVAL: "2m"
PRUNE_BACKUPS_DAYS: 2
# method info
BACKUP_METHOD: tar
DEST_DIR: /backups
TAR_COMPRESS_METHOD: zstd
ZSTD_PARAMETERS: "-11 --long --single-thread"
volumes:
# IMPORTANT: Must mount to same location as server data volume above
- ./data:/data:ro
# Where the backups will be saved to
- /media/HDD/game_backups/mc/ATM7/0.4.24:/backups
# share network namespace with server to simplify rcon access
network_mode: "service:minecraft"
```
And receiving the following error:
```
Unable to execute rcon-cli save-on - try 0/5. Retrying in 10s
Failure reason: 2022/08/06 Failed to RCON serverdial tcp 127.0.0.1:25575: connect: connection refused
```
Running on headless Ubuntu. I've tried looking at some of the other bug reports here with similar issues, but I can't seem to figure this one out. Is this expected since I'm specifying `tar` mode?

Start with the minecraft and backups service definitions in the provided compose file, focusing on network_mode, SERVER_PORT, and the RCON connection error. Check the relevant container logs and RCON configuration to determine why 127.0.0.1:25575 refuses the connection. Done means the backup service can run its RCON command successfully in tar mode.

Written by the indexing model from the issue text.