Kong Manager Network Error

I have 2 Kong setup with Kong Manager enabled, 1 Kong OSS in Docker, and 1 Kong Enterprise Free Version in Ubuntu.

Both my Kong Manager works when using http://localhost.com/, however both has the same issue of having Network Error under the Workspaces overview.

The configurations that I have edited in kong.conf are as follows:
admin_listen = reuseport backlog=16384, http2 ssl reuseport backlog=16384
admin_gui_listen =, ssl
admin_gui_url = http://localhost:8002/
admin_gui_path = /
admin_gui_api_url = http://localhost:8002/

This is the error displayed on Google Chrome Console:

GET http://localhost:8002//default/kong net::ERR_CONNECTION_REFUSED
GET http://localhost:8002//workspaces?size=15&sort_by=created_at&counter=true net::ERR_CONNECTION_REFUSED

Can anyone please let me know if I missed out on any other important configurations or did I edit any of these configurations wrongly?

I can provide more details as to what I have done in the setup, or whatever necessary.

Can you change the following?

admin_gui_api_url = http://localhost:8002/ to http://localhost:8001 (admin api)