TerraMaster Forum

Hi everyone.

Lost connection with my F5-221.
Currently has 3 x 6TB HDD.
TOS: 5.1x

Current methods tried without sucess:
-Reboot
-Reset button
-SSH access: denied
-Reinstall TOS via Method B described here ( the 3 beeps are audible): viewtopic.php?t=423
Always TOS5x
1) Tried via online install
2) Tried via downloaded package

I can re-establish connection when the disks are removed and reinstalling the TOS.
After achieving 100% of installation and rebooting, i'm unable to connect again.
Tried via:
-TNAS PC
-SSH
-Browser (witch clean cache)

I only can ping the TNAS.
What options do I have from here?

lmrp wrote: ↑21 Jun 2025, 20:04

Is your device discoverable via the TNAS PC application?

What does the manifestation of being unable to access look like? Please provide a screenshot.

Before attempting access, please ensure both your NAS and your computer have IP addresses within the same local area network.

Both PC and Nas are in the same local Area network.

The device is not discoverable. The only exception that I found out was during reinstallation of the TOS, when i startup the NAS without the disks.

The manifestation is not being able to access via SSH, TNAS PC, TNAS Mobile or IP of the nas via browser.

Hello!
Regarding the issue where the F5-221 device still cannot be recognized by the TNAS PC client or TNAS Mobile client after reinstalling the system, we recommend the following troubleshooting steps:

First, log in to your router’s management interface to check the current IP address assigned to the F5-221 device. Also, verify whether any access restrictions (such as MAC address filtering, port blocking, or DHCP allocation issues) have been configured on the router, as these factors may prevent the client from detecting the device properly.

Hi! Thank you for the support.

The router management without any filters or restrictions, IP adress is currectly allocated.
After rebooting and reset button again, ensured i had ping and runned NMAP to check what was open.

SMB is currently available with default login, but not possible to open or edit folders.
:8181 - Now opens, but frozen on displaying "Loading..., please wait!"
TNAS PC still doesn't detect anything.
SSH Still not available

Hope the information below can provide some idea on how to solve it

lmrp wrote: ↑23 Jun 2025, 05:56

I hope the following link can be helpful to you:
viewtopic.php?t=2407

lmrp wrote: ↑23 Jun 2025, 05:56

Have you at some time enabled Firewall rules or other restrictive connection settings? Attempts to ssh in fail because, according to your nmap data, Port 22 is not open. Some things like ssh and telnet access have settings in GUI to allow/deny. {Just a thought}.

Hi everyone,

After 2 days fully on, the system and I was able to login and perform all configurations.

After initial setup, tried to restart, and was a quick "normal" restart, with full access.

No more issues so far - so I would consider it solved.
Did any user before reported something similar?

Well, same issue appeared again.
After a rebooting, the device in the network is not found.

Now, not even in the router appear any IP, however I can see the network port blinking.

Any idea?

Your symptoms seem vaguely familiar, and this might be an unnecessary question, but are you certain that you had followed the upgrade procedures for TOS5.1 and allowed a now o/s partition of 8GB {Edit } to be created?