Attachments from 3rd party app won't send

I am using iPhone 6+ with 8.3 iOS. I have been trying to send an attachment from a 3rd party app (Hours) from within the app and it acts as if the e-mail sends as there is the "swoosh" sound and the e-mail disappears from the screen, however, it is never received. I am sending from a g-mail account. I also have this issue when trying to send a photo by e-mail or text from within the photos app. I have to send photos from within the mail app for them to go. And, all works fine from my iPad (iPad Air 8.3 iOS). I have researched this for sometime and cannot seem to locate an answer to my specific issue. Any help would be appreciated. Based upon the research, I have already done a reset and re-boot of the phone, as well as deleted and re-installed the e-mail account. The attachment is not large---a simple .pdf or .csv file that is not large. Any photos are not overly large either. I have also checked the gmail account through the web and when sent from the phone, the Hours file / e-mail was found in the "All Mail" folder one time (there were multiple sends) but the attachment had been stripped.

Thanks everyone. I appreciate any suggestions.

---Jean