Hello

I got hands on a bunch of Antminer U1 and started playing around with them. After getting the right drivers I started mining to give-me-coins.com and all worked fine for 2-3 days (I could see my hashrate and earnings on the pools website)
Now I checked and the pools website doesn't show any connected worker, where bfgminer is still working fine and reporting accepted shares screenshot.
I didn't change anything, neither on the pools website nor in the batch file I start bfgminer with. What to do? Where to start with troubleshooting?

Thanks in advance