hi! I am getting a similar error that was mentioned below for (March 8th) but for April 3rd/4th. Enjoying the game otherwise so far!
This was already reported by another player, but it will take longer to fix. I didn't program more days after April 3rd because I thought all the players would get an ending, good or bad, before that, so now I need to extend the days, let's say a week more. Make a save of your game and maybe start over and go for another route in the meanwhile? Remember there's a guide, too, if you want to go straight to one route more easily.