AWS EC2实例Drupal 8站点访问被拒绝

I have just migrated a Drupal 8 site to AWS EC2 instance. Everything seems to be working except for one thing - when I log in, I get Access Denied message.

It appears that the website validates the user admin credentials and redirects to the correct page at user/1 but the authentication cookie/session are not handled properly.

I have found this ticket but am not sure how much it pertains to my situation since I am not using (as far as I know) the Cloudfront.

Password access not working with AWS Cloudfront website using Drupal

Any help or advice on this is appreciated.