Cannot add Google account for syncing, e.g., Google calendar to Mac calendar
I'm using Mac OS Mojave 10.14.6. In System Preferences, Internet Accounts, I click to add my Google account. It takes me to a Google pop-up window in Safari to enter my Google username and password. After entering my correct Google username and password I receive the following error message in System Preferences, Internet Accounts: "Authentication Failed. Failed to authenticate with Google, please try again later." At Google's end, it thinks everything's fine. I receive a Gmail message from Google stating: "macOS was granted access to your Google Account." This has happened repeatedly over several weeks. Solution?
Mac mini 2018 or later