Symfony 4 - User becomes null on callback from external API service - symfony

Question

On Symfony 4, when catching a callback route from any external API service (in this case - Shopify API), my logged in user becomes anon.
(HTTP): Everything works when testing on localhost
(HTTPS): However, my logged in User becomes null / Anonymous when testing on my remote server (prod).
How do I fetch my logged in user after catching a callback route from any API service? I think it could be a problem with either HTTP vs HTTPS or some Symfony settings.
On Shopify API dashboard - Allowed redirection URL(s):
http://localhost:8000/shopify/callback
https://<myremoteip>.com/shopify/callback
Symfony Controller Route (for Shopify callback):
/**
* #Route("/shopify/callback", name="shopify_callback")
*/
public function shopify_auth_callback(Request $request)
{
dd($this->getUser());
}
Callback Result (localhost):
App\Entity\User {#977 ▼
-id: 103
-email: "aaaa#gmail.com"
}
Callback Result (remote):
null

Answer 1

I had the same issue but with the Google Oauth system.
I just changed the cookie samesite policy in framework configuration from 'strict' to 'lax' and it solved my issue
Now I can keep the user logged in after api redirection
framework:
session:
enabled: true
cookie_secure: 'auto'
cookie_samesite: 'lax'
cookie_lifetime: 86400

Answer 2

The problem was that I was creating a new session before navigating to a remote URL.
Advice for future readers - make sure you're always on the same session, which you can fetch from the Request.
Avoid doing this:
$session = new Session();