400: Bad Request - Fully Kiosk

Configuration
1

Hi,

i have two samsung a9+ tablets. both in the same network as homeassistant.
both tablets has the same config and running fully kiosk app

both use the same user for login.

since some days, on of the tablets show me the error “400: Bad Request”

i cant open the homeassistant dashboard. when i open it with chrome on this tablet it works well. the homeassistant native app, works too.

i dont know what suddenly happend and why the other tablet doesnt have this problems.

is there any firewall / blocking in homeassistant for some ip + browser engine (because chrome works well)?

thanks for any advice.

2

Are they both displaying the same dashboard at the same time?
What is being attempted to be displayed when the error is encountered?
Is the problem consistently one device or does it swap around? Any other issues such as poor battery charging, or network reliability?
Is there any added apps on each tablet? Antivirus? Firewalls? Custom firmware? Have you gone back to factory settings and reinstalled identical software on each? Are the tablets used exclusively for kiosk displays or have other uses?

3
  • same dashboard
  • same software
  • build in wall, not swapping
  • problem since couple days constant on one of them.
  • no special apps, samsung stock, except fully kiosk
  • they both have no acces to wan/internet. blocked. (but even if remove the firewallrule, the error stay)
  • both tablets are only for this purpose.
  • exported and imported the config via remote in fully kisok. they are equal.

this error happen out of nowhere

homeassistant always on the latest stable version.

as i mentioned , chrome and nativ ha-app works without problems.
and kiosk worked the last 2 years too. (and still works on the other tablet)

edit:
i already remove all website and cache data from fully kiosk.
when i add google as startpage in fully this works. its only homeassistant. thats i i throught something like a build in firewall, too many request, idk…

4

What are you using as startpage? Is it http://homeassistant.local:8123 or http://yourIP:8123?

5

homeassistant ip

6

i have no complete reinstalled, and imported the same settings into fully as before. and now it works.

had to re-enter my account settings and done.

works again. idk. but the error 400: Bad Request was defnetly from Homeassistan, and i found nothing inside the HA logs (like, "not authorized, tried to many times … ").

7

Weird. Does fully kiosk have logs or maybe a dev console (like chrome’s F12) you can look at?

8

i have now completely reinstalled and imported the same settings into fully as before - now it works.

had to re-enter my account settings and done.

works again. idk. but the error 400: Bad Request was defnetly from Homeassistan, and i found nothing inside the HA logs (like, "not authorized, tried to many times … ").

9

if u use remote admin, you can check the fully logs, but same i found nothing. because it looks like HA was correct loaded, could be http 200. but it shows 400: Bad Request, this wasnt a “regular browser error screen”

10

No errors on HA Core logs?

11

i had some, but i thought the are from the fully integration. like:

Logger: homeassistant.components.fully_kiosk
Quelle: helpers/update_coordinator.py:461
Integration: Fully Kiosk Browser (Dokumentation, Probleme)
Erstmals aufgetreten: 22. Dezember 2025 um 17:28:01 (2 Vorkommnisse)
Zuletzt protokolliert: 22. Dezember 2025 um 20:28:40

Error fetching 192.168.0.250 data: (500, "Remote admin server can't find a running Fully activity...")

maybe it was an kiosk app/browser fail. hmmm. anyways. it works now.

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