You need to supply information so the forum can understand your setup. What OS are you using? Windows 10 or MAC OS ? What version of Thunderbird are you using? Did the problem occur immediately after a Thunderbird update? What Anti-Virus product are you using? Are you talking about an Imap or Pop mail account? Is the problem only with receiving email or is there a problem sending as well? Do you have other mail accounts/email address which are receiving ok - so it is just the one account ? Is Thunderbird in Online mode? - If it is Offline then that explains why there is no access to internet. What error message do you get when you try to 'Get Messages'? - post image of it. What server settings are you using - post info of the following: In Thunderbird * Help > More Troubleshooting Information * Scroll down to 'Mail and News Accounts' section * Copy all the data and post it into this forum question.