Mail app can't open Safari to log into Gmail account
I recently changed the password to one of my Gmail accounts. When I try to log into that account through Apple's Mail app, I get a dialog box telling me that Mail needs to finish the log in via Safari. So I click the "Open Safari" button -- and nothing happens (except the button grays out). It appears that Mail and Safari can no longer communicate with each other.
I recently updated to Safari 13.0, in case that's the problem.
Other third-party mail apps have no problem logging me into this account, even with the new password.
Anyone else running into this?
MacBook Pro