vibe.d Error only with Firefox

[crimaniak]

On Friday, 5 January 2018 at 16:30:07 UTC, Martin Tschierschke 
wrote:
...
> Failed to listen on 127.0.0.1:8030
> Failed to listen on 10.0.0.1:8030
...
> The strange thing is now, that when using Chromium 
> http://10.0.0.1:8030 works!
> But with Firefox http://10.0.0.1:8030
> gives the long Error:
> 400 - Bad Request

I would first figure out what happens to the port 8030. Run this 
command before and after starting the application to see who is 
really listening:
sudo netstat -nlp | grep 8030