Can't Start Conquest Battles

Try a different node. I also lost 60 energy. 

I'm not saying this shouldn't be fixed, but as a workaround temporarily you can try other attackers or other nodes. 

The node that kept eating my energy was Challenge Path, Nightsisters (MT Lead), 2 from the end Boss of s2. (End boss is Ad Raddus, then one node back toward the beginning along the Challenge Path, then one more, and that was my NS node that would lock up.) 

Fortunately I was at the last branch when I could chose to go another direction, and when I left the CP things worked. I finished the last 2 nodes before AdRad. Now I'm going in to check to see if AdRad works... 

AdRad (End boss s2) worked. My attackers were JMK, Snips, GK, POW, MQG.