Baby leaning to one side in carrier?

For some reason my 4 month old leans to one side while I baby wear. Is this normal? I think all the straps are right, but it's my first time wearing him. any suggestions? Edit: @Mallory I think so too, but I can't figure out what it is. From the manual all the straps are in the right place (I think, the manuals not very helpful) 😂 Edit: @Gwen there's no way I can get his arms underneath the straps, he's just too big 😢 I think I got him in a better position today but he's a bit fed up with the experimenting haha