When going into the Labs it initiates Strigo.
Then you are supposed to take the DNS address and paste it into another web browser to go there.
It works the first time you do it but after that if you stop and go back in it then will fail and give a 404 error. The way I corrected this and continued on anyway was to use the IP address instead of the DNS in the address bar, then it goes to the lab instructions and Kibana it correctly.
Each time you pause and resume a lab, your virtual machine may get a new IP and DNS. After you resume, you should be able to get the updated IP/DNS by clicking the gear and selecting "Machine Info".
There's a relatively new addition to the "Machine Info" popup: it now also shows you a "Dynamic DNS". This will stay the same, even if you pause/resume your lab. Using this "Dyamic DNS" instead of the "Public DNS" will be more convenient.
That is actually exactly what I've been doing.
Pause>Resume>Grab new DNS... fails. (so used IP address instead which worked)
However you did state now the Dynamic DNS should not change and should be good regardless so I now know that is an option.