also

} else if (err.errType === supertokens.Error.UNAUTHORISED) {
                // redirect to login page.
            } else {    // TRY_REFRESH_TOKEN
                res.status(440).send("Please call the refresh token endpoint");
            }

It says 'redirect to login page', what code do you need to write to do that? and 'TRY_REFRESH_TOKEN', <-- Does this mean we have to code that in or leave it as

res.status(440).send("Please call the refresh token endpoint");