Hmm, I don't know enough to give you a confident answer yet. The error

ERR_HTTP_INVALID_HEADER_VALUE

typically indicates that there's an issue with the headers in your HTTP request. However, without more specific information about your request and the context in which you're seeing this error, it's hard to diagnose the exact problem. In the context of Ory, when making a request to the

/self-service/login/browser

endpoint, you need to ensure that you're setting the correct headers. For example, if you're initializing a login flow for a server-side browser client, you should set the

Accept

header to

text/html

([source](https://www.ory.sh/docs/kratos/self-service/flows/user-login#login-for-server-side-browser-clients)). If you're initializing a login flow for a client-side (AJAX) browser client, you should set the

Accept

header to

application/json

([source](https://www.ory.sh/docs/kratos/self-service/flows/user-login#login-for-client-side-ajax-browser-clients)). Please review your request and ensure that you're setting the correct headers. If you're still encountering issues, you might find it helpful to review the [Ory API Reference](https://www.ory.sh/docs/reference/api) and the [Ory Kratos User Login Documentation](https://www.ory.sh/docs/kratos/self-service/flows/user-login).

The error message you're seeing indicates that the value for the header

x-vercel-internal-timing

is

undefined

. This could be due to a misconfiguration in your request or server setup. However, the knowledge sources provided do not contain specific information about the

x-vercel-internal-timing

header or how to resolve issues related to it in the context of Ory. It's recommended to check your server configuration and the code where you're setting this header. Ensure that the value for

x-vercel-internal-timing

is correctly defined and is a valid HTTP header value. If you're using Ory behind a reverse proxy or load balancer, make sure that it's not stripping or altering the headers in a way that could cause this issue ([source](https://www.ory.sh/docs/self-hosted/hydra/debug/csrf#reverse-proxy-or-load-balancers)). If you're still encountering issues, you might find it helpful to review the [Ory API Reference](https://www.ory.sh/docs/reference/api) and the [Ory Troubleshooting Documentation](https://www.ory.sh/docs/troubleshooting/csrf).