emails leaving inbox not arriving anywhere

have been sending emails and they are not arriving at destination, no bounceback, nothing,  they are sitting in the sent items folder fine, have checked all the details of the account and it is set up correctly. have 2 accounts on the same em 1 is working 1 is not

Hi Sam,

can you please test sending your email to yourself?
I also suggest to consult this matter with your email provider as emails which are moved to Sent folder are managed by mail server.