DS1307RTC Outputting cryptic 165/165/2165 date. What are some possible fixes?
Put in the following line in void setup():

Wire.begin();


(Assuming Wire library has been included.)
This will set up the I2C connection between the Master (Arduino) and the Slave (RTC).

For more generic use, the syntax is: Wire.begin(address);

The complete code is:

void setup () {
  Wire.begin();
  Serial.begin(9600);
  //rtc.adjust(DateTime(F(__DATE__), F(__TIME__))); // UNCOMMENT TO SET TIME &amp; DATE TO THAT AT COMPILATION.
  //rtc.adjust(DateTime(2017, 8, 31, 14, 45, 14 )); // UNCOMMENT TO SET TIME &amp; DATE MANUALLY. (YEAR, MONTH, DAY, 24-HOUR, MINUTE, SECOND) 

}