I have no idea how or what your emailing looks like, but I was having the same problem. Emails I sent weren’t getting received by her. Also when I checked the Sent folder, it didn’t show it there either.

I have an iphone, and I figured out that it was sending the emails from my icloud email, instead of gmail. I never changed any settings, so I have no clue why it was doing that. I was using the regular mail app for my emails. I downloaded the actual gmail app, and every email I sent through there has gone through.

Just posting my experience just in case yours is similar.