Has anyone experienced lag on the iPhone 6S Plus?

ive been experiencing some lag issues with my iPhone 6S Plus. Has anyone else noticed this? I have restored it twice and sometimes what will happen is iMessage will lag in group chats and frequently, Airmail can barely be used.

I have also noticed everyone now and then my iPhone will state that a call has failed, and today noticed for a couple hours messages would not go through via iMessage, text were fine though. The message would state it was delivered but minutes later would come back stating it has failed. I would choose try again and they would deliver instantly and successfully.

could his be an Apple server issue?