My typing bar always disappeared on my group text

I have this group text on my iPhone that we text each other every day but since 5 days ago my texting bar disappeared. Only me. I received everyone’s text but I can’t write back. I have erased the text group and stated all over again. That fix the problem temporarily for one message then I have to reset the chat again and again every time I want to say something to them. How can I fix that. It’s really annoying and a problem to look for a group of people every single time you have to say something to them. Technology already has a solution for that. But your company has problems with this.