Played Minecraft just fine last night. This morning, it can't find the internet?

Would not stop saying 'Play offline', no matter what troubleshooting I did or how long I waited.

Tried logging out and logging back in, but whenever I enter my information, it says it can't connect to the internet and log me in. That's the launcher's problem, as I'm typing this on that same computer.

Even tried deleting the launcher and re-installing it. Didn't work. Neither did restarting my router.

My spouse can login and play online just fine on their computer (same specs), so it's not the servers. What is going on?