添加“重试”导致我丢失了回溯

目前我有一个这样定义的脚本:

import traceback
import logging
import time

logging.basicConfig(level=loggings.DEBUG)
logger=logging.getLogger(__name__)

if __name__ == '__main__':
    try:
        main_code()
    except Exception as e:
        logger.debug(traceback.format_exc())
        error = traceback.format_exc()
        with smtplib.SMTP("mailhub.global.company.com") as mailServer:
            msg = MIMEMultipart('related')
            msg['Subject'] = Header(u'Test', 'utf-8')
            msg['X-Priority'] = '2'
            body = "Delivery Failure, the following exception occurred:\n\n" + str(error)
            msg.attach(MIMEText(body, 'plain'))
            mailServer.sendmail("email@gmail.com", ["email@gmail.com"], msg.as_string()) 
            mailServer.quit()
        print("Exception occurred- delivery failure email sent")

如果出现错误,我会收到一封带有回溯功能的电子邮件。

我尝试在失败的情况下向代码添加“重试”,以便它尝试5次,中间5秒,如下所示:

if __name__ == '__main__':
    for attempt in range(5):
        try:
            main_code()
        except Exception as e:
            print("Error occurred, retrying in 5 seconds!")
            time.sleep(5)
            continue
        else:
            break
    else:
        logger.debug(traceback.format_exc())
        error = traceback.format_exc()
        with smtplib.SMTP("mailhub.global.company.com") as mailServer:
            msg = MIMEMultipart('related')
            msg['Subject'] = Header(u'Test', 'utf-8')
            msg['X-Priority'] = '2'
            body = "Delivery Failure, the following exception occurred:\n\n" + str(error)
            msg.attach(MIMEText(body, 'plain'))
            mailServer.sendmail("email@gmail.com", ["email@gmail.com"], msg.as_string()) 
            mailServer.quit()
        print("Exception occurred- delivery failure email sent")

但是,由于某种原因,当我现在收到一封发送失败邮件时,它只会说: Delivery Failure, the following exception occurred: NoneType: None

知道如何将跟踪返回到发送的电子邮件中的错误吗?