White boxes displaying on Blue LCD 16X2 Display

got lcd 16x2 display , ran "hello world" sketch on arduino.

the following thing happens after uploaded sketch arduino uno:-

1.lcd gets power on

2.white boxes gets displayed on 1st row of lcd

3.nothing gets displayed on 2nd row of lcd.


varying potentiometer leads increase/decrease of contrast of white boxes displayed on lcd.

what do??
please help!

it means not connecting lcd.  something missing.  either connections, or code wrong (does not match connections).

show connections.

post link picture of setup - perfectly focussed.

read instructions how post code, post code actually using.

please not "attach" things.

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