How to restore access to shellinabox?

Question

SSH

Ubuntu Server is installed on a Windows 10 computer in a Hyper-V virtual machine After upgrading from Ubuntu 15.10 to 16.04, access to shellinabox (a daemon providing ssh access through a browser) was lost
ps ax | grep shell
27329? Ss 0:00 /usr/bin/shellinaboxd -q --background=/var/run/shellinaboxd.pid -c /var/lib/shellinabox -p 4200 -u shellinabox -g shellinabox --user-css Black on White: +/etc/shellinabox/options-enabled/00+Black on White.css,White On Black:-/etc/shellinabox/options-enabled/00_White On Black.css;Color Terminal:+/etc/shellinabox/options-enabled /01+Color Terminal.css,Monochrome:-/etc/shellinabox/options-enabled/01_Monochrome.css --no-beep 27330 ? S 0:00 /usr/bin/shellinaboxd -q --background=/var/run/shellinaboxd.pid -c /var/lib/shellinabox -p 4200 -u shellinabox -g shellinabox --user-css Black on White: +/etc/shellinabox/options-enabled/00+Black on White.css,White On Black:-/etc/shellinabox/options-enabled/00_White On Black.css;Color Terminal:+/etc/shellinabox/options-enabled /01+Color Terminal.css,Monochrome:
netstat -an -pt | grep shellinabox tcp 0 0 0.0.0.0:4200 0.0.0.0:* LISTEN 27329/shellinaboxd
Port 4200 is forwarded in the router settings. From host shellinabox is accessible via https://192.168.1.6:4200 , but outside, via external IP and domain name - no - "Connection attempt failed"
Tell me, what could be the problem?

Answer 1

After rebooting the host everything worked.