Based on the information you gave me, I also entered the page and tried it, and I have successfully joined. I think you have a network problem. You can try to refresh it a few times, and then you can express your love for her on the signature wall. This is a screenshot I took after participating in the event. I hope I can give you a satisfactory answer, haha!
Domineering nickname: 1. Domineering nickname: I miss you, traveling backwards, cold dust, warm tea, first meeting,