An error occurred while uploading the sketch.

pert:
Please do this:

  • File > Preferences > Show verbose output during: > compilation (uncheck) > upload (check) > OK
  • Sketch > Upload
  • After the upload fails you'll see a button on the right side of the orange bar "Copy error messages". Click that button.
  • Paste the error messages in a reply here USING CODE TAGS (</> button on the toolbar).

it'll be great if i could get some help too

< Arduino: 1.8.7 (Mac OS X), Board: "Arduino/Genuino Uno"

Sketch uses 4300 bytes (13%) of program storage space. Maximum is 32256 bytes.
Global variables use 239 bytes (11%) of dynamic memory, leaving 1809 bytes for local variables. Maximum is 2048 bytes.
/Applications/Arduino 2.app/Contents/Java/hardware/tools/avr/bin/avrdude -C/Applications/Arduino 2.app/Contents/Java/hardware/tools/avr/etc/avrdude.conf -v -patmega328p -carduino -P/dev/cu.usbmodem1421 -b115200 -D -Uflash:w:/var/folders/4j/p2g4zhc94990rcsc7khsbyrh0000gn/T/arduino_build_479303/sketch_dec15a.ino.hex:i

avrdude: Version 6.3-20171130
Copyright (c) 2000-2005 Brian Dean, http://www.bdmicro.com/
Copyright (c) 2007-2014 Joerg Wunsch

System wide configuration file is "/Applications/Arduino 2.app/Contents/Java/hardware/tools/avr/etc/avrdude.conf"
User configuration file is "/Users/ifrahs/.avrduderc"
User configuration file does not exist or is not a regular file, skipping

Using Port : /dev/cu.usbmodem1421
Using Programmer : arduino
Overriding Baud Rate : 115200
avrdude: ser_open(): can't open device "/dev/cu.usbmodem1421": No such file or directory

avrdude done. Thank you.

Problem uploading to board. See http://www.arduino.cc/en/Guide/Troubleshooting#upload for suggestions.

This report would have more information with
"Show verbose output during compilation"
option enabled in File -> Preferences.
/>