I'm assuming you are using the most up to date version of Thunderbird which is version 115.11.1 However, you need to supply more information on the current situation. Q1: What OS are you using - Windows 10, MAC, Linux etc ? Q2: What version of Thunderbird are you using? Q3: What Anti-Virus product are you using? The following info will tell us what account server settings you are using. In Thunderbird * Help > Troubleshooting Information * Scroll down to 'Mail and News Accounts' section * Copy all the info in that area and paste data into this forum question. * OR create an image and upload it showing all info in that section. When you try to 'Get Messages' what happens ? Do you get an error message ? If yes, then what does it say word for word? The info at this link offers good info on server settings: https://help.iinet.net.au/email-settings