<![CDATA[Local host error 431]]>I am using OperaGX as my browser. I am a developer and I am running web applications, which visual studio hosts on local host.
After an HTTP request is triggered, i get a:
"This page isn’t working
If the problem continues, contact the site owner.
HTTP ERROR 431"
When i host a website with a domain, I have no problems. The problem is only with local host.
I read that deleting the cookies will fix the issue, which it did fix it, but logged me out from every website I ever used. The problem came back a few hours after I deleted the cookies. I have no issues if I start my application on any other browser. I can delete the cookies once again, but if that fixes the problem only for a couple of hours with the cost of signing me out from every website, what's the point?
I've used OperaGX for a few years and I've never had this issue. I don't know if a recent update is causing this, but I would really appreciate any help, because I don't want to switch broswers.

]]>https://forums.opera.com/topic/72733/local-host-error-431RSS for NodeMon, 16 Mar 2026 12:40:32 GMTWed, 03 Jul 2024 09:38:55 GMT60<![CDATA[Reply to Local host error 431 on Thu, 04 Jul 2024 09:26:10 GMT]]>@burnout426
Thank you very much. Didn't know the option to delete the data only for a specific domain (in my case local host) existed. That fixed my isssue.

]]>https://forums.opera.com/post/354922https://forums.opera.com/post/354922Thu, 04 Jul 2024 09:26:10 GMT<![CDATA[Reply to Local host error 431 on Wed, 03 Jul 2024 23:37:03 GMT]]>@martinkulev said in Local host error 431:

I read that deleting the cookies will fix the issue, which it did fix it, but logged me out from every website I ever used.

You can goto the URL opera://settings/content/all and search just for 127.0.0.1 or localhost or whatever to narrow down the results just for the local server and click "Delete displayed data". That way, it won't log you out of other sites.

]]>https://forums.opera.com/post/354906https://forums.opera.com/post/354906Wed, 03 Jul 2024 23:37:03 GMT<![CDATA[Reply to Local host error 431 on Wed, 03 Jul 2024 23:35:27 GMT]]>Are you using http://127.0.0.1/ or http://localhost?

HTTP ERROR 431

I see that can be caused if one of Opera's request headers it sends (like Referer) are too long or if too many cookies are sent. Since you said clear cookies helps for a bit, it might be the latter. But, not sure why Opera would be different compared to other Chromium-based browsers.

Does it happen with a test standalone installation of Opera too?

]]>https://forums.opera.com/post/354905https://forums.opera.com/post/354905Wed, 03 Jul 2024 23:35:27 GMT