accounts not downloading

Today I set up a new mail account on thunderbird using ' tools->account settings->add account'. Although there are messages on the server for the new account, TB fails to download the waiting messages. There are no error messages and TB appears to loop. The inbox for the new account remains empty. The new account uses the same pop and smtp [mail.btinternet.com] as the main account .Messages from the original account still download successfully. TB can send messages to and from the new account so it is only the download from the server that is failing. I have previously [early Feb]been successful with downloading from bt subaccounts using that pop server

 

http://support.mozillamessaging.com/bg/kb/Configure+an+Account

Maybe the Port is wrong?

 

I think that I reported my dislike of TB3.x because of its unfailing inability to create correct servers. Invariably, I have had to use manual setups. And, even that has created problems, because the original, incorrect, settings were entered in my antivirus, and I had problem with the AV blocking the server as they had it. It is no problem with existing accounts, imported from TB2.x, but new accounts are a headache, at best. Please compare your settings, of the new account, if the same provider as the existing account.
I have Cox as my ISP, and TB came up with an IMAP setting, and for POP, settings like mail.cox.net or pop.cox.net, with every possible Port. The same goes for the SMTP.
My account is a regional one, so the general one is wrong. I contacted the developers, and was not assured that I could set up my account like the old days, by myself, but they admitted that there are "issues ". Hardly a day goes by that I don't find some problem, and since the new 3.3 nightlies are as bad as the present 3.1.8, I am willing to take a chance with 2.0.0.24.