I’m having some email problems..for some reason when I send an email with large attachments it disappears, its not in my sent items, outbox, drafts or archives...and there is no error message.

I have my zoho account on outlook and thunderbird same problem. 

If i send the same email and attachments on my Hotmail account it works fine any ideas?

Is there any way I can recover these emails to help me work out which have not been sent?