09-15-2025 04:05 AM
Is anyone else experiencing issues accessing the Labs? I am receiving the error "400 Bad Request, Request Header Or Cookie Too Large"
Solved! Go to Solution.
09-15-2025 11:46 AM
Always use an incognito or private browser.
09-15-2025 04:17 AM
Hello @MichaelParker, welcome to the community!
You will need to elaborate a bit for us to be able to help you. Are you talking about the collaboration devnet sandbox? dCloud?
09-15-2025 11:07 AM
09-15-2025 01:33 PM
No problem! As @bigevilbeard suggests it is often useful to try from a incognito/private browser tab, especially when you get a 400 error. In my experience there are unfortunately multiple Cisco sites are prone to this issue, so you will probably face it again at some point.
09-15-2025 11:46 AM
Always use an incognito or private browser.
09-16-2025 02:13 AM
Unfortunately "...Request Header Or Cookie Too Large" is a known problem with SSO across Cisco sites, this is not specific to the DevNet sandboxes. Clear your browser cookies and auth again.
Incognito mode works as well given you will not have cookies.
This happens when you visit many Cisco sites, they add a string to your cookie as a list (I'm not an expert on this part, but this is what I vaguely remember) which might become too big for some browsers and then you will get this error.
It would be good to document somewhere, but not sure where is a good place so more users can be aware of it.
09-16-2025 02:27 AM
@Jesus Illescas normally i love me a large cookie, but i dont think we are taking chocolate chip here?
09-16-2025 02:37 AM
@bigevilbeard I'd wish we refer to those cookies, then it wouldn't too big.
09-18-2025 10:55 AM
@Jesus Illescas, do you know if this is an issue someone is working to solve? It has been like this for quite a while...
09-19-2025 01:53 AM
@Torbjørn I haven't heard any news on a team working on it, only what our DevNet engineering shared with me. That's a downside of a big company. I'll try to find out, but no promises.
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