I sent a message to the contact us section already but since it looks like I'm not the only one I'll put in my two cents. This is happening to me as well for the past few days. Everything else seems to be working as intended, except no new quests anymore. I have it set to PVE only, if that makes a difference, and I've never changed it, nor have I ever rerolled a mission.
It still has a countdown to when the next quests are put out, but they never drop.