Doesn't just reopening the window using your browser history reconnect you to the game? If not, that's very weird. 
The site gives plenty of time to get back to the game if you're disconnected~
https://support.chess.com/article/338-how-does-game-abandonment-work
Thanks for your reply, Abhi. The incident that triggered that post - just over three weeks ago -- was one in which nothing seemed to work. I have avoided any reincidence of the problem since then: I won't make the mistake of navigating away from a game by following some link elsewhere on the screen while my opponent either things or is waiting for THEIR computer to reconnect. Best to just keep planning my next moves -- I keep a pen and paper handy for noting my options and likely responses. // It does seem like a situation that the admin team (or the team of software engineers behind the scenes?) might wish to further study sometime. Set this up, simulate it with ... simulated subscribers. But I'll continue doing my best NEVER to need to find out whether the problem recurs.
How do I return to an active "live" game if I (foolishly) navigate away?
Example: today I was in a match. I escaped a checkmate due to ... let's call it good fortune. I followed the link to my adversary's profile.
At that point, I was unable to return to the active game. I trued multiple approaches, all failed. I was only able to view the game after it finished. Apparently, despite time on my clock, my absence from the "board" triggered a resignation. Not a bad ending considering the position, but ... the question remains:
..... How do I return to a live match if I navigate away?
Thanks. Feel free to comment on comparable Q's, such as returning after a browser crashes and you must log back in.
-DL