Did you not download the update that was made available 5 days ago? If you download it now you will need to redo Hitomi's past quest again to open timeline 2.
Viewing post in Version 0.3 Bug Reports
It was fixed in the latest version with a fail safe that doesn't need you to redo Hitomi's quest again if you haven't changed it to True Timeline already. But since you already changed it, you will need to reset and redo Hitomi's past quest. Or you can edit something in save file located in C:\Users\USERNAME\AppData\LocalLow\LAGS\RingManSpiritHunt. Make sure to make a backup first then look for "timeline2Unlocked": 0 and change it to "timeline2Unlocked": 1.