'Sent' means that the mail has been transmitted from the outgoing server of your email provider. That's all. The analogy with 'snail mail' is that you've written and addressed the letter and put it in the post box of the mail company. There's no guarantee it will arrive at the destination. In the case of email, your email provider sends your message to servers run by other companies, and they send it on to others. If the chain is broken at any point (e.g. if a server refuses the mail) an error message should be transmitted back to the originator, but that doesn't always happen. Steps you can take to investigate it are: - contact your email provider and ask them if they can help: give details of specific messages you sent (date, time, addressee etc.) that you know did not arrive - ask your son to check his junk/trash folder in case your messages are going there by mistake - check your own junk/trash folder in case error messages sent to your account are ending up there - send a couple of test emails to your own account to check that it's working properly As you say, the problem is not uncommon. Email is great when it works properly but it's very far from being perfect. (BTW none of this has anything to do with Thunderbird, which is just software that lets you access your email account.)

Hi thank you for replying to my post I find it hard to believe it's not a Thunderbird problem because the e-mail recipients used to receive mail from me before Also as the mail account is a derivative of Yahoo (rocketmail.com) I can send e-mail directly from the yahoo home page on the same PC even bbc to the same account Whenever I do they get through straight away Therefore doesn't seem to be related to the receiving server This started when bcc's back to myself weren't received and now progressed to my son's account which is gmail I also have a yahoo account and that receives mail fine so not even limited to Yahoo Graham

So Rocketmail doesn't deliver any BCCs you set in Thunderbird?

There is a known problem using BCC with Outlook.com (Hotmail / Live / Outlook addresses): https://support.mozilla.org/questions/1126573. It seems to be a block on the server side.

Hopefully this isn't becoming a trend with SMTP clients.

It also doesn't work if it's "to" Just tried sending a test e-mail to myself from thunderbird and nothing does it work for you? it used to for me

I don't have Thunderbird on this computer, so I can't test at the moment. However, I can't think of any reason you shouldn't be able to send yourself an email from the same account.

It shows up in Sent items but not in Inbox?

Because there have been floods of spam spoofed to come from peoples' own addresses, some users may have a junk filter on their own address. If you ever set up one of those, please check your Junk folder.

checked jund and deleated just in case and nothing there weird it works from yahoo mail tho.

I can think a at least one reason for sending to yourself fail. If you use Gmail they simply do not show you the mail. you have a copy in your send folder, they do not show it to you again. A common example of this is with mailing lists where you email the list server and never see your own mail to the list. Gmail eats it.