Notify people to attend birthdays and how to avoid them if they have something to do and cannot go there at the moment

You can contact your friends privately first to explain that you are indeed having trouble, and then send a photo of yourself, say you are sorry, and let your classmates have fun. This will appear polite and will not disappoint anyone.

Usually the reason for replying to text messages is family. For example, a relative came to my hometown and I was embarrassed to leave him alone at home, or he needed to go to the hospital to see a doctor. Of course, I could also say that he had been feeling unwell for the past two days and his blood pressure was a bit high. In other words, the unit leader has arranged work and must work overtime to complete it tonight