Logon directly to your webmail account via a browser to see if the server is receiving new mail. Are there new unread emails in the webmail server Inbox? If no then that explains why there are no new emails being downloaded to Thunderbird nor phone. In Thunderbird, is the account a Pop or Imap account ? What server are you talking about eg: gmail ? If no new emails are arriving on the server then maybe you have reached maximum allowed quota - basically it's full so cannot accept anything. Suggest you delete a load of old emails off the server - please note if you use a Pop account this will not have any effect on emails in Thunderbird. BUT if you have an IMAP mail account in Thunderbird then it displays whatever is on server, so you would need to get 'Copies' of emails put into the 'Local Folders' account before you delete those emails off the server. Otherwise you will lose them.