When using the Synology Active Backup for Business (ABB) Agent on Linux, you may encounter a common hurdle: if the NAS IP address changes or the server goes offline permanently, the agent often gets stuck. The standard logout command abb-cli -l fails because the agent insists on contacting the original server to de-register.
This guide shows you how to manually break the connection and reset the agent without a full reinstallation.
The Problem: abb-cli -l Fails Without a Connection
Normally, you would use abb-cli -l (logout) or abb-cli setup to reconfigure the agent. However, if the agent cannot reach the original NAS (e.g., after a server migration or IP change), it will return an error:
“Internet error. Please check your Internet connection… Authentication failed.”
Since the agent is stuck in a “logout loop,” you must clear the configuration at the file level.
Step-by-Step: Manual Connection Reset
If the regular logout is impossible, a manual intervention in the agent’s SQLite databases is required. Follow these steps:
1. Stop the Service
First, stop the agent’s background service so the database files are not locked:
sudo systemctl stop synology-active-backup-business-linux-service
2. Delete the SQLite Databases
The agent stores its identity and server IP in SQLite databases. In current versions, these are located in the /data/ folder. We will specifically remove them:
sudo rm /opt/Synology/ActiveBackupforBusiness/data/system-db.sqlite
sudo rm /opt/Synology/ActiveBackupforBusiness/data/log-db.sqlite
sudo rm /opt/Synology/ActiveBackupforBusiness/data/temp.sqlite
Note: Ensure you use the .sqlite extension, as older documentation often incorrectly refers to .db files.
3. Remove the SSL Certificate
Because changing the IP often causes SSL handshake errors due to cached certificates, you should delete the old certificate file as well:
Bash
sudo rm /opt/Synology/ActiveBackupforBusiness/data/certs.pem
4. Restart the Service
Now, restart the service. It will automatically generate fresh, empty database files upon startup:
sudo systemctl start synology-active-backup-business-linux-service
Establishing a New Connection
Now that the old configuration remnants are gone, the agent will act as if it were a fresh installation. You can now easily launch the connection wizard:
sudo abb-cli -c
(Alternatively, sudo abb-cli setup will now work perfectly without any “Already connected” errors).
Enter the new IP address or hostname and your admin credentials. The agent will now be recognized by your Synology NAS as a new device (or allow you to relink it).
Pro-Tip: Summary of Commands
# Force Reset Script
sudo systemctl stop synology-active-backup-business-linux-service
sudo rm /opt/Synology/ActiveBackupforBusiness/data/*.sqlite
sudo rm /opt/Synology/ActiveBackupforBusiness/data/certs.pem
sudo systemctl start synology-active-backup-business-linux-service
sudo abb-cli -c
Conclusion
A “stuck” Synology Linux Agent is frustrating but easily fixed by clearing the local SQLite databases. A complete uninstallation (which often incorrectly reports massive disk space usage on Linux) is not necessary to solve connection issues.