Unable to access current e-mails after migration from old Mac

To copy all Thunderbird e-mails from my old Mac I had copied Thunderbird profile "oldname.default" from the old Mac to my new Mac and changed to names in profile.ini to "oldname.default". Now I see and access on my new Mac all my old e-mails, all folders and address book. But Thunderbird stopped downloading any new e-mails from the server, so I am unable to receive e-mails. What I did wrong? Vladimir