Cannot send or receive iMessages

I have been having some issues sending and receiving texts on my iPhone 8 lately. Whenever I text it says not delivered. Even when I send as a text message. Though my friend received the texts I sent as a text message despite it saying not delivered for myself. The only person I can text is my friend who does not have an iPhone. I recently tried to turn off messages in settings and turn it on again. And now it just says waiting for activation and will not activate my messages at all. So I can no longer text anyone. I am unsure how to fix this issue.