Thunderbird is email client software running n your computer. Once it hands the message off to your providers SMTP server it is done. It has no control over the delivery after that point. Ask your provider why your messages are slow to be delivered.

Hello, I am not referring to the delivery of emails but the reception of emails. Regards, Paul.

OK, same story. Thunderbird displays messages that are in the Inbox of your account on your providers server. Are these missing messages on the server when you check there?

Hello, I do not know they are missing or even that they exist until they arrive on my computer. Regards, Paul.

A1A1 said

Hello, I do not know they are missing or even that they exist until they arrive on my computer. Regards, Paul.

It is common for large mail providers to simply drop connections from smaller new mail servers and in the case of some of the big US firms refuse to deliver mail until X attempts have been made or X days have elapsed since the first connection attempt.

Looking in the message headers (ctrl+U to access message source) to see where the delay in delivery occurred can be useful. The header lists every step of the delivery from when the person presses send until you get it, all with time stamps. So the point of delay can be established.

You might also find, if your using a corporate mail system, that the mail was diverted to a local "might be spam" on the server and sat there until a server admin checked it and decided it was not spam.

Hello, Thank you for this information. It may well be the problem. I have looked at the information provided by tapping ctrl +u and there is a great mass of it so i wiil spend more time looking at it when another late email shows up. By the way my emails come from roundcube. Regards, Paul