message recieved as random letters and numbers and symbols

Hi there! So recently like in the past week or so, my phone has stated doing this thing, where my boyfriend will send me a long text message and when I receive it, it’s a random string of letters, numbers, and symbols. But if he sends me the message somewhere else like on Twitter, the message shows up just fine. I’ve tried resetting and updating my phone but nothing seems to be working. Does anyone know how to fix this?