Connexion Problem with arduino

#1

Hi! I cannot communicate to an Arduino Uno with mBlock v4.0.4 to upload firmware of communication . when I select “Update Firmware (USB)” the Upload job fails with “Cannot communicate with the board” ! Any suggestions would be greatly appreciated! Thank you

#2

Please take a screen shot of the error page.
How did you connect the board to mBlock? USB or?
Do you have another board for testing except Arduino Uno?
How about testing mBlock 3? mBlock 4 is the experimental version.