SvelteKit unable to set cookie - cookies

Question

Using SvelteKit 1.0.0-next.571
My application has a login route with:
+page.server.ts => redirects to / if locals.user is set
+page.svelte => show login page
signin/+server.ts => Login and get a jwt from graphql app running on the same machine.
+server.ts:
[..]
let gqlResponse = await response.json();
if ( gqlResponse.errors ) {
console.log("ERRORS FROM GRAPHQL MIDDLEWARE:", gqlResponse.errors);
return json( { error: gqlResponse.errors, isException: true } );
}
if (gqlResponse.data.login.user && !gqlResponse.data.login.error) {
opts.cookies.set('jwt', gqlResponse.data.login.token, {
path: '/',
maxAge: SESSION_MAX_AGE
});
opts.setHeaders( { 'Access-Control-Allow-Credentials': 'true' } )
opts.setHeaders({ 'Content-Type': 'application/json' })
}
return json( gqlResponse.data.login );
and the login handler in +page.svelte :
[..]
const fetchOptions = {
method: 'POST',
//mode: 'no-cors',
//redirect: 'follow' as RequestRedirect,
body: JSON.stringify(credentials),
credentials: 'include' as RequestCredentials
}
try {
const response = await fetch('/login/signin', fetchOptions);
const login = await response.json();
if (login.error) {
handleError(login);
return false;
}
} catch (e) {
return handleException(e);
}
goto('/', { replaceState: true, invalidateAll: true} );
This works fine in localhost, but connecting another device to the local network does not set any cookies making impossible to login:
Local: http://localhost:5173/
➜ Network: http://192.168.x.x:5173/
I also tried with different fetch options and cookie settings like:
opts.cookies.set('jwt', gqlResponse.data.login.token, {
path: '/',
httpOnly: true,
sameSite: 'strict',
// secure: true
maxAge: SESSION_MAX_AGE
});
but no luck, and now 'm stuck.