OC200 Captive Portal Authentication Fix

I am currently experiencing issues with the OMADA CONTROLLER OC200 external captive portal developed in PHP. Users are unable to authenticate due to a persistent error after inputting their credentials. The specific error message they receive states "can't connect to server 192.168.100.66:443, contact your server administrator".

Ideal Skills and Experience:
- Experience with OMADA CONTROLLER OC200
- Understanding of captive portals
- Capability to troubleshoot and solve server connectivity errors

Please apply if you can effectively diagnose and resolve this issue, ensuring smooth user authentication moving forward.