Please check Run/Build Configurations to see if you set any run params there. if yes?

remove --web-renderer, because if youre using the flutter latest its not gonna work with any '--web-renderer' because now flutter team made these changes :

Make --web-renderer=canvaskit the new default (the current default is auto).

Remove --web-renderer=auto.

and you can simply build using

flutter build web

if you face any more problem please let me know, i would be happy to help you out.