express-openid-connect added routes (/login /logout) fail (not found 404)

Same app. /login fails (route not found) with this code:

app.use(/^(?!\/api).+/,
    auth({
        auth0Logout: true,
        issuerBaseURL: process.env.ISSUER_BASE_URL,
        baseURL: process.env.BASE_URL,
        clientID: process.env.CLIENT_ID,
        secret: process.env.SECRET,
        authRequired: false,
    })
);

This works (no regex):

app.use(
    auth({
        auth0Logout: true,
        issuerBaseURL: process.env.ISSUER_BASE_URL,
        baseURL: process.env.BASE_URL,
        clientID: process.env.CLIENT_ID,
        secret: process.env.SECRET,
        authRequired: false,
    })
);

Why? I want to use the middleware only for routes that don't begin with /api. How do I accomplish this?