Email body wording not there when checked in sent items

I wrote two emails yesterday and each had an attachment. I sent them, but when I checked in my sent items, the wording in the body of the email had vanished. There is a little brown envelope at the top left of this sent message saying "Message" but it won't open. I don't know how this has happened, and the emails sent now make no sense to my clients without the wording. can anyone tell me what happened, and how to fix this

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