Text message forwarding (null) for iPhone SE to iPad

Hello! For a while now I’ve stopped receiving text message forwarding on my iPad, although the setting was enabled on my iPhone SE to do so. To try and trouble shoot I disabled it on my iPhone. Upon reenabling it, I receive an error ‘(null)’ message on my iPad instead of a code to pair the devices. I’ve tried restarting both of them, turning off iMessage, turning iMessage back on on both of them, all the basic troubleshooting steps. My MacBook Pro (running macOS Sierra 10.12.6) has also stopped receiving Text Message Forwarding at the same time. When trying to disable and reenable Text Message Forwarding for my MacBook on my iPhone, nothing happens. It looks as if it has enabled it, but it does not ask for a pairing code, nor recieve Text Messages. My text message forwarding worked perfectly for a long time and no changes were made to any settings. The only changes were installing iPhone software updates. I believe one of the recent iPhone software updates has caused this. My iPad has had the same software on it (10.3.3) the entire time. Any ideas to further trouble shoot are greatly appriciated!