Internet Accounts in System Preferences hangs/freezes

I needed to change the password for one of my "Internet Accounts," but there was nowhere to do it in System Preferences. I deleted the account, planning to add it back, but now every time I click "Google" to add it back, it says that it requires completing authentication in my web browser. When I click "Open Browser," it opens a small window (presumably trying to open Safari, which is not my default browser), then hangs. It jumps to the back of my screen, behind any other windows, won't let me click on it anymore, and just shows a spinning loading icon indefinitely until I click "cancel."

I tried opening Safari and logging into the Google account first, and when I tried to add it with that window open, it took me through the authentication process in the little Safari window, but never brought me back to Internet Accounts, which remained untouched despite the fact that I had just authenticated my account. When I tried to replicate this, it just got stuck like I described above.

I need access to this account. How can I get it back?