Only several rifts didn't start due to the server issues. Most rifts were still running. That are: 1 am, 4 am, 10 am, 1 pm, 10 pm.
For those players who missed the Titan rifts due to the server issues yesterday: you'll be able to complete this quest today during the fight with Titan. We'll spawn the quest NPC not far from Titan so you could complete the quest for Iola and Golem kills during the battle and accept a new quest for Titan right away. In that way players who missed the rifts yesterday will be able to complete 2 quests today and get a Titan Branch and main event rewards.