[Help] F4-423 TOS web UI Not loading

[peewii16]

Hey all,

My F4-423 has suddenly stopped loading the web UI.

Browser shows “Loading, please wait…” or sometimes ERR_CONNECTION_REFUSED.

SMB still works fine → I can access all my files.

Port scan shows 8181 open (nginx), 139/445 open (Samba), but no SSH.

Tried multiple browsers, cache clear, reboots.

TNAS PC tool can’t detect it, even with manual IP.

Removed drives and powered on → TNAS Detects It

Problem is, the F4-423 doesn’t have a reset button, so I can’t do the usual recovery trick.

I’ve read I may need to use a USB bootloader + TOS install package (6.0.783) to reinstall the OS partition, which should keep my data intact.

Questions:

Has anyone done a USB recovery reinstall on this model — did it preserve your RAID/data volume?

Is there any way to force recovery/SSH without USB?

Any other troubleshooting steps before I reinstall TOS?

Thanks — I don’t want to risk wiping my disks, but I need the web UI back to manage this box.

[TMnight]

Based on your description, you can try the following two solutions:
1、Since you are currently unable to log in via SSH, you can attempt to restart the NAS device or directly connect a monitor and keyboard to the NAS and start the SSH service through the command line. If you can successfully log in to SSH from your computer, we can arrange for an engineer to remotely inspect the device's condition.
2、Try reinstalling the TOS system. Typically, reinstalling the TOS system will not affect the data on the hard drives, so you can attempt this operation to resolve the issue.

[peewii16]

which tos system should i be reinstalling and should i be using the hard drive removal technique as described or is there another method

[TMjack]

Hello, if the USB bootloader can successfully recognize TOS version 6.0.783, you can proceed to install this version directly.