body of forwarded emails appearing as attachment to recipients

my clients often tell me that there was nothing in the emails I sent them. I know for a fact I forwarded a trail, but they say nothing is there, they received a 'blank' email (apart from my written message referring to the trail I forwarded). It transpires, the forward emails were there but as attachments that the client then had to click on to open and read. Is there any way around this? I've looked in all settings, but can't find a way around it. The body of the forwarded message is still coming in as an attachment to the recipient.

Thanks 😕