Gmail won't send emails with attachments

Hello,

So my Gmail is contacted to my Samsung tablet, iPhone and 3in1 hp computer and for some reason I can upload attachments and it'll say I sent them. But it won't reach the recipient. My daughter played around with it and by chance she fixed it but 2 days later it's doing it again.
My emails send if they're normal, no attachments of course.

Can anyone help please?