Emails are the primary source of communication with your customers. When the emails do not get delivered, it is a hindrance to your regular pace of work which we would definitely not want you to face. A few basic checks before reaching us would be:
Creating an SPF makes sure Emails are delivered efficiently.
Sometimes, the client email address might be in the drop address for which you could contact us to clear this right away.
If this needs more assistance, kindly write to us (firstname.lastname@example.org) so that we can help you better.