Every now and then, something like half of Microsoft’s websites will suddenly stop working – this applies to Azure Portal, SharePoint Online sites, MSDN forums and probably a thousand of other sites. The error is most of the time something like this:
Bad Request - Request Too Long HTTP Error 400. The size of the request headers is too long.
Or like shown below:
This effectively blocks you from accessing the site. Most typically, I’ve encountered this on MSDN forums or Azure Portal – I’ve just faced a very blunt, unfriendly and quite useless error message, like above.
Yet once again, the solution is almost stupidly simple.