It’s confirmed that due to political issues, foreign websites are temporarily slowed down in China. I have fixed the problem via VPN. Thanks for everyone’s help:)
Since yesterday, I have problem connecting to the community website. I’ve tried a lot of other websites, like fpltoif, simbrief, to test if it’s my ISP’s problem. I’m currently living in Shanghai, China, and some people here may know how my government blocks websites. But they can’t block IFC because there’re no political issues of China on this forum. I don’t know what kind of problem it is, so I think I’d better ask about this on the forum. Another interesting thing is I am now connecting via my 4G network, instead of Wi-Fi, because 4G uses CN2 to connect with foreign websites, and it’s a lot faster. That’s the only way I can think of now to connect.