Hi there! It sounds like you've hit a bump with sending Outlook messages after updating to Thunderbird 115. Don't worry, we can get this sorted out! It's great that you've already tried reinstallation, which can help sometimes. Let's give this a shot: First, double-check your SMTP settings for your Outlook account in Thunderbird. Make sure they're correctly configured. Also, ensure any antivirus or firewall isn't interfering with sending. Sometimes disabling them temporarily can help troubleshoot. If the issue persists, you might want to try removing and re-adding the Outlook account in Thunderbird again. Sometimes a fresh setup can fix these quirks. Give it a go, and let's see if that gets your Outlook messages flowing smoothly again! If not, we're here to help.

Thanks for your help. None of that worked because the problem is in Thunderbird 115 itself. I've switched to Betterbird that works fine.