People not receiving mails i send

Question

For the last 5 days, only one of my emails has reached its recipient. The others are all lost somewhere... When I send, everything appears to be fine, but they are not arriving. Would be very grateful for any help

Answer 1

When a message is successfully sent (a message will remain in the Outbox and not be moved to the account's Sent mailbox if not successfully sent), the message is either accepted or rejected by the recipient's incoming mail server.
If rejected by the recipient's incoming mail server for whatever reason, you will receive a return email error message from the recipient's incoming mail server indicating why the message was rejected.
All or most incoming mail servers have a spam filter and virus scan. If a message is accepted by the recipient's incoming mail server, the message may be incorrectly marked as spam and if the message includes an attachment, the attachment may be infected with a Windows virus if a received message from a Windows user includes an attachment and is forwarded by you. False positives also occur but regardless, the attachment (correctly or incorrectly determined to be infected with a virus) is usually removed from the message at the incoming mail server and the rest of the message is available for download by the recipient.
Basically if a message sent by you is accepted by the recipient's incoming mail server, the problem lies at the recipient's incoming mail server or between the recipient's incoming mail server and the recipient's email client.