It's hard to say exactly what tipped the government sponsors over the edge to banning Go Princess Go but Caixin writes:

China's government has showed its disapproval of programs that depict time travel before. In 2011—when several shows featuring protagonists going back to ancient times were popular—it issued guidelines that said production companies were discouraged from making them because they "lack positive thoughts and meaning."


The website reports that censors have suddenly begun paying closer attention to internet series, some six years after they started being produced by streaming services like LeTV, the company behind Go Princess Go. The show attracted 2.4 billion views, according to Quartz.

[h/t Shanghaiist]