Login failed code=9406 with UGOS firmware 1.15.1.0127

[JuananAros]

Problem description

After updating UGOS to firmware version 1.15.1.0127, the integration
fails to connect with error code 9406:

login failed code=9406 msg=El cliente no es compatible con el firmware,
¡por favor actualice el cliente!

Environment

• Integration version: v2026.05.3
• NAS model: UGREEN DXP4800 Plus
• UGOS firmware: 1.15.1.0127
• Home Assistant version: 2026.4.3

Steps to reproduce

1. Update UGOS firmware to 1.15.1.0127
2. Restart Home Assistant
3. Integration fails to login with code 9406

Log extract

ERROR (MainThread) [custom_components.ugreen.api] [UGREEN] login failed
code=9406 msg=El cliente no es compatible con el firmware,
¡por favor actualice el cliente!

ERROR (MainThread) [custom_components.ugreen] [UGREEN NAS] Initial login
failed. Aborting setup.

Additional info

The integration was working correctly before the firmware update.
After the update it is no longer possible to connect regardless of
reinstalling the integration or re-adopting the NAS device.

Can anyone confirm this issue with firmware 1.15? Is there a workaround
available while a fix is being developed?

Thank you for your great work on this integration!

[Tom-Bom-badil]

I am exactly on that version, no any issues.

Could it be that the error message is misleading, and it is 'just' a communication error? We've had this before, but months back with older firmware versions - same error message. Reason was always a communication problem in the LAN.

I suggest following the steps in the discussion "Troubleshooting guide for installation + auth errors" (pinned on top).

/tom

[indiggio]

I'm getting the same 9406 error when trying to log in.
I've verified the curl command with the api_token works fine, but the integration fails to authenticate.

2026-06-11 16:01:09.964 ERROR (MainThread) [custom_components.ugreen.api] [UGREEN] login failed code=9406 msg=The client is not compatible with the firmware, please update the client！

I just noticed I'm on 1.16.0.0089.
I did some "ChatGPT"ing about this and it appears that UGREEN has changed the login protocol for the WUI that seems to have broken the auth method that's being used in this integration.

[Tom-Bom-badil]

I'm not at 1.16 yet, but this report is even on 1.16.1.0018 on a new idx model. So I doubt the login has changed. Did the AI give you any reference / source on that statement, or was it just halluszinating one more time?

Did you check all the items in the Troubleshooting guide? In other discussions, 9406 was caused by enabled 2FA on the dedicated admin user.

/tom

[indiggio]

Yes, I gave AI the api.py to reference. Used Chrome DevTools to trace the protocol and the UGREEN does not seem to like not having token= on the check URL.
Yes, I went through the entire troubleshooting guide.
The troubleshooting guide says that it's mimicing what's being done in the login process, but the login api.py code is doing
url_pk = f"{self.base_url}/ugreen/v1/verify/check?token="
I don't see any test in the troubleshooting section that's performing a curl to this endpoint?

[Tom-Bom-badil]

Again - I don't think it's a changed login mechanism in the new firmware. With the amount of users we have (1k users listed on HA analytics, which only covers 1/4 of the HA user base), we would have more reports on that already. Also, the first link I provided above reports even a newer firmware than yours, just look it up yourself: "system_version":"1.16.1.0018". I am pretty sure the problem sits somewhere else - question is: where?

/tom

edit/ps: You can of course try: http://nas_ip:nas_port/ugreen/v1/verify/check?token=your_token. That's what api.py is doing as well, as you already found out yourself. But that doesn't bring us much further to identify the problem. Is HA running on the NAS itself? HAOS or container?

[Tom-Bom-badil]

Heya @indiggio,

any news on this?

Just fyi, I updated today to the exact version you have installed. No changes in the login procedure / authorization; the integration is working as usual and without errors. So your problem is either with:

• your admin user you use for login (2FA off?),
• your NAS setings (auto-port redirection disabled?),
• your HA VM or container settings (Linux bridge mode enabled?).

Just keep me posted on the progress, good luck! :)

/tom