Hello folks, I’m new to this 3d printing wolrd.. and got two issues when printing the red wing sign… 1. i noticed there are several patholes on the front surface, it looks like there wasnt enough filament on those spots. 2. at the back, i noticed there are dark residue spots, it looks like something over burnt and was left in it. i printed this item once and i didnt have this issue before, just wondering how can i solve it, thanks!