I too am getting "Pool Connection Lost" errors on Mine77
ports 7777 and 7788
Which miner? I still get them if I use xmr-stak-amd (tried it on 4 different rigs and all available ports) but sgminer-gm-nh works fine on port 7777. Weird as I'd been using xmr-stak-amd for a couple of days with no problems until the pool daemon was restarted earlier today.
I am using stak's miner as well, the Nvidia version.
It was working perfectly before. My errors also began after the daemon's restart on the pool.