When you create a question, it is helpful to provide some information so we get some idea about your particular situation. '''Q: '''What OS are you using - Windows 10. MAC, Linux ? '''Q: '''What version of Thunderbird are you using ? In Thunderbird * Help > More Troubleshooting Information * scroll down to 'Mail and News Accounts' section * Please post/upload an image jpg showing all the data in that section. This will tell us the type of mail account you are using and the name of server you are trying to use and all the smtp server settings currently in use. '''Q: '''When you try to send what happens? '''Q: '''Do you get an error message ? If yes, '''Q: '''what does it say word for word ? - or post an image of the error.