If you see this error trying to open Simulate, work through these steps in order.

400 Bad Request
Request Header Or Cookie Too Large
nginx

This error usually happens when your browser has built up saved login data from being signed in to multiple GovWorx tools recently. Clear your cookies for govworx.net (Settings → Privacy → Clear browsing data → Cookies), then sign back in and try Simulate again.

If clearing cookies doesn't fix it right away, open Simulate in a private/incognito browser window. This loads the page without any saved cookies and confirms whether the fix worked.

If the error persists in both a normal and a private window, try a different browser entirely.

If none of the above resolves it, message us with your browser name and whether the error happens every time or only occasionally — we'll take a closer look.