I can remotely access the Gateway (docker image) when my laptop is on mobile data but when using wifi internet I got the errors (connection reset, SSL certificate error)
Note: I forwarded the ports 8080 and 4443 on my router and can access the Gateway using my public IP address but not the webthings domain name
Is the router blocking access on the internal side to resources on the external side?
Depending on your router operating system, it can be quite difficult to work out the cause and resolution.