I using EM Client on the phone and PC simultaneously and I have problem with disappearing both send and inbox email messages after certain time on both devices. They totally disappear, nothing in trash and other folders. On brother PC and phone every message from begining of using EM is there. Is there any help to prevent this? My email is: firstname.lastname@example.org
How is your email account configured(IMAP, POP3, Exchange etc.)?
Have you done some changes or adjustments in settings before this occurred?
Can you please also check if your emails disappearing from webmail too?
It can caused by settings on some device which is using your account, what you are probably using on your phone is email account itself not eM Client as we have only PC version.