Issue uploading pictures though docker


I was wondering if someone could shed some light, Currently installing gitlab on docker, but when i try to upload pictures on the wiki im getting server responded 0

on firefox i ran debug and said it was something with

Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at http://266f7874aef7/api/v4/projects/5/wikis/attachments. (Reason: CORS request did not succeed). Status code: (null)

on chrome it showed this

266f7874aef7/api/v4/projects/5/wikis/attachments:1 Failed to load resource: net::ERR_NAME_NOT_RESOLVED

im was checking on the docker config but not sure which part i need to change the URL which i think its pointing to localhost instead of the URL

i tried to edit this part of the gitlab.rb

## GitLab URL
##! URL on which GitLab will be reachable.
##! For more details on configuring external_url see:
##! Note: During installation/upgrades, the value of the environment variable
##! EXTERNAL_URL will be used to populate/replace this value.
##! On AWS EC2 instances, we also attempt to fetch the public hostname/IP
##! address from AWS. For more details, see:
 external_url ''

this is my nginx


    server {

#        listen 80;
   listen 443 ssl;

  ssl_certificate /etc/letsencrypt/live/;
        ssl_certificate_key /etc/letsencrypt/live/;
        ssl_protocols TLSv1 TLSv1.1 TLSv1.2;
       ssl_prefer_server_ciphers on;
        ssl_dhparam /etc/ssl/certs/dhparam.pem;
        ssl_ciphers 'EECDH+AESGCM:EDH+AESGCM:AES256+EECDH:AES256+EDH';
        ssl_session_timeout 1d;
        ssl_session_cache shared:SSL:50m;
        ssl_stapling on;
       ssl_stapling_verify on;

location ~ /.well-known {
        root /var/www/letsencrypt;
        allow all;
        location / {


                # headers setting

                proxy_set_header Host $host;

                proxy_set_header X-Real-IP $remote_addr;

                proxy_set_header X-Forwarded-For $remote_addr;

                proxy_set_header X-Forwarded-Proto $scheme;

                proxy_set_header X-Client-IP $remote_addr;



Thank you