Where and when are drk job quests past 50?

Im 53 drk right now and I have not seen the next job quest spawn. Can u guys tell me when and where are the rest of the job quests please?

Tnx

You probably skipped the L50 quest that chains in Coerthas. Head to Whitebrim Front somewhere near the mailbox and there should be an L50 quest for you. This can be confirmed by seeing which quest goes red if you swap classes.