How can I resolve an SSL/TLS error when using Thunderbird SMTP?

SSL/TLS errors often indicate a mismatch between the Thunderbird configuration and the SMTP server's security requirements. Ensure the correct SSL/TLS encryption method is selected in Thunderbird (STARTTLS is generally recommended). Verify the server's certificate is valid and trusted. If using custom SSL certificates, ensure they are properly configured in Thunderbird. Older or outdated Thunderbird versions might also have compatibility issues.