There are several things that could cause this.
incorrect pins being used, incorrect wiring, bad/broken wires, or incorrect pullup resistors.
My suggestion would be to use my hd44780 library. The hd44780_I2Cexp i/o class included in the library is for hd44780 LCDs that are using a i2c backpack.
The library will auto locate the backpack i2c address, and self configure the pin mappings used between the backpack and the LCD.
It should "just work" with your LCD device.
If it doesn't, the library also includes a diagnostic sketch that will test the i2c connections, the backpack and the LCD.
The library can be installed using the IDE library manager.
Here is a link to the github page for more information: https://github.com/duinoWitchery/hd44780
It also has information about installation and which IDEs are compatible.
While IDE version 1.7 should work ok, at some point you should consider upgrading to a newer IDE version as there have been many useful updates and bug fixes since then.
Use the library manager to install the hd44780 library. Do not download it from the github page and install it using a zip file.
Here is a link to the wiki for additional information about the library and the i/o classes:https://github.com/duinoWitchery/hd44780/wiki
The i/o class for your device is hd44780_I2Cexp.
I'd recommend first running the diagnostic sketch, I2CexpDiag, to make sure everything is working correctly.
The diagnostic sketch will print information on the serial port about the tests and any issues that it may find.
After that is working, then look at the HelloWorld sketch to see what header files need to be included and how to declare the lcd object.