Go you your providers web mail page and see if the email in in your Inbox there. if it is not in your Inbox Thunderbird cannot download it. Maybe it keeps going to your Spam folder.

Number one, how do I go to my web mail page and how do I get into my spam folder????

Thanks

I have no idea who your provider is so that is impossible to answer. I use Comcast so I go to Comcast.net and people that use gmail go to google.com.

Comcast is my server and I checked that and didn't find anything and checked spam and nothing was there. What else can I do????

Were the missing messages in your Comcast Inbox? If not Thunderbird cannot download them. You need to ask Comcast where your email is going.

As a realtor I get many, many e-mails for my business and personal messages daily and this is the first time I can recall that a message didn't come through. I remember getting a message asking if I wanted to compact my messages and I believe I answered "yes". Do you think this could have caused the problem??

Compacting folders removes messages you marked for deletion. Deleting a message marks it for deletion and hides it. Compacting removes it and frees up the space. This should be a regular maintenance task. Bottom line, if the message does not make it into your Inbox on the providers server Thunderbird cannot fix that or download the message. Do you have Threading turned on? View-Sort By-Unthreaded Sometimes with threading turned on a new message on a previous subject can get filed with an old message and not be obvious.

How would I find that Threading is turned on or off and how do I view-sort by unthreaded. This was a threaded message that I could not get, I believe.

Thanks for this possible help.

You go to the View menu and click Sort By and see if Unthreaded is checked. View is on both the menu bar and the AppMenu button. Pressing the alt key reveals the menu bar and the AppMenu button is 3 horizontal lines usually in the upper right corner.

nothing is working but thanks for helping, I appreciate your concern

Not sure what "nothing" means. Did you check the sort by screen?