# What OS are you using? # What version of Thunderbird are you using? # What server are you talking about eg: gmail, outlook, yahoo, comcast etc ? # What Anti-Virus are you using ? What happens when you click on 'Get Messages' and when you attempt to send an email? Do you get an error message of any type? It would be helpful to see images of the error messages. Always adviseable to do the following to check nothing is blocking access. '''Firewall:''' Access Firewall - it might be the default supplied with OS or if you installed an Anti-Virus then it's probably controlling the Firewall. You must set up the Thunderbird program as 'allowed'. This will then stop blocking of ports etc. Do not stop Firewall as the default may take over and anyway you need it running. Confirm Firewall has Thunderbird program set as allowed. '''Anti-Virus:''' Access Anti-Virus and set up an exception to not scan your Thunderbird profile folder. If you download Thunderbird from the official website : https://www.thunderbird.net/en-US/thunderbird/all/ Then default would have put the 'Thunderbird' profile folder here: * C://Users/username/Appdata/Roaming/Thunderbird Confirm Anti-Virus not allowed to scan Thunderbird profile folder. Please post info regarding your server settings. Helpful to upload images of 'Account Settings' > 'Server Settings' for the account to this forum question. Also locate and post this info: * In Thunderbird - Help > Troubleshooting Information * Scroll down to 'Mail and News Accounts' * Copy all data in that area and paste it into this forum question. Access your webmail account via a browser and check to see if any emails have arrived on the server. Did you get access to webmail account ? Did it have new emails that have not been downloaded to Thunderbird account ? Please report back with info.