Hello,

I noticed something strange.

When I enter the address for the relay server in the client configuration of the REMOTE machine, I can connect to the remote site.

CANNOT connect:

CAN connect:

No, here is the compose file in case it helps:

services:
  hbbs:
    image: rustdesk/rustdesk-server-pro:latest
    container_name: hbbs
    ports:
      - 21114:21114
      - 21115:21115
      - 21116:21116
      - 21116:21116/udp
      - 21118:21118
    command: hbbs -r 192.168.85.142:21117
    volumes:
      - ./hbbs:/root
    networks:
      - rustdesk-net
    depends_on:
      - hbbr
    restart: unless-stopped

  hbbr:
    image: rustdesk/rustdesk-server-pro:latest
    container_name: hbbr
    ports:
      - 21117:21117
      - 21119:21119
    command: hbbr
    volumes:
      - ./hbbr:/root
    networks:
      - rustdesk-net
    restart: unless-stopped

Please set relay server pubic ip or domain explicitly here. In your case, the deduced relay server ip (because you do not set it explicitly, and you RustDesk client and hbbs are in the same intranet) is local ip sometimes, so causing problems.

I guess your problem is here， please remove -r 192.168.85.142:21117

Removing -r 192.168.85.142:21117 from the compose file and the relay server in the console got it working.

Any idea why this used to work and then suddenly stopped?

Also, in what cases can clients communicate without passing through a relay server?
And in what cases must they use one?