Messages on MacBook are sending as SMS instead of iMessage after update

I recently updated my MacBook to MacOS Sequoia 15.4.1, and ever since my messages are either sending as SMS instead of iMessage, or just flat out failing to send. Messages are also not syncing completely.

I've logged in and out of iMessage, restarted my MacBook, signed in and out of iCloud, and so on. Text message forwarding is enabled and correctly set up on my iPhone.

This seems to be an issue other people are having too.

Any suggestions? Thanks!