The "send" botton just get grey when I try to send message

I am a chatgpt plus user. Since the day before yesterday, when I try to send message to chatgpt in my browser on PC, the "send"botton just trun to grey, and there is no any other error message. However, if I log out my account and use chatgpt anonymously, it works well.
I have tried to clean cookies, use gpt4 or 3 instead of 4o, and switch to another browser, but nothing changed.
This situation happens on my Edge on PC and on the Chrome on iPhone. However the mobile app for iPhone works well.
I wonder what happened and how to fix it.