For a long time I write emails but when I click on the send button I get a message from:  *** Email address is removed for privacy ***  saying that [ delivery status notification (failure) according I lost confidence in my mail adress secondly

a- is this *** Email address is removed for privacy ***  authentic

b-what is the origin of it

c- why are emails not send

do- I have to trust the so called postmaster

thanks