Email: [Firebase] Client access to your Cloud Firestore database expiring in X day(s)

The easiest way to overcome this expiry is to change the date in the rules after logging into the account:
match /{document=**} {
// from previous date 2020, 11, 11 to new date 2021, 12, 11
allow read, write: if request.time <, 12, 11);

However, do note that it is important to drop access using this method once done with the database. Use this only for testing test databases.