If the SSH toggle turns itself off a few seconds after you enable it, first update off old beta builds and check the SSH service rather than repeatedly flipping the switch. The source case happened on ZimaOS 1.6.0 beta2 and was handled by IceWhale support, but no public root cause was posted.
Current ZimaOS has a supported SSH toggle under Settings → Developer Mode. Since 1.6.2, remote root login is disabled by default for security, so use a normal ZimaOS account unless you specifically need root and have configured it locally.
Enable SSH the Current Way
The current ZimaOS SSH guide documents Settings → Developer Mode → SSH Access.
If the Toggle Immediately Turns Back Off
systemctl status sshd
journalctl -u sshd --no-pager -n 100Record the error before restarting anything. A service that cannot start because of configuration, key, filesystem, or port problems will often make the UI toggle revert.
Check Port 22
ss -ltnp | grep ':22'If another service already owns port 22, SSH cannot bind normally. Do not change the port until you know what is listening there.
Root Login Changed in ZimaOS 1.6.2
The official ZimaOS 1.6.2 release notes says remote root login is disabled by default and brute-force protections were added.
Use a ZimaOS User Account First
ssh youruser@ZIMA-IPTest with the same local account that works in the ZimaOS UI. A failed root@... login is not proof that SSH itself is broken.
Use the Web Terminal as a Separate Test
If ttyd/Web Terminal works but SSH does not, the shell environment is healthy and the problem is specific to the SSH service or network path.
Do Not Reuse a Beta-Specific Workaround
The source thread ended after remote support and did not publish a verified command-line fix. On a current release, collect logs and fix the current service state instead of copying undocumented beta edits.
The system troubleshooting guide provides a wider escalation path.
Check Whether the System Can Create Host Keys
SSH needs readable host keys and writable system state. If logs mention missing or invalid host keys, do not download keys from another machine. Let the current ZimaOS service generate or restore its own keys through supported recovery.
Test from the Same LAN Before Remote Access
Connect from another computer on the same subnet before debugging routers or VPNs. If local SSH works but remote SSH does not, the service itself is healthy and the problem is routing, firewalling, or your remote-access design.
Do Not Port-Forward SSH Casually
ZimaOS already provides remote-access options that avoid exposing management ports directly. If you need shell access away from home, prefer a private VPN/overlay network or another authenticated path over raw public port forwarding.
FAQ
Why can I not SSH as root anymore?
ZimaOS 1.6.2 disabled remote root login by default as a security hardening measure.
Does SSH require Developer Mode?
Use the supported Developer Mode SSH toggle on current ZimaOS.
Why does the toggle switch itself off?
Usually the backend service failed to stay running. Check systemctl and logs for the real error.
Should I reinstall ZimaOS?
Not before checking version, sshd state, port 22, account type, and logs.
