我正在使用debain jessie,certbot版本0.9.3-1〜bpo8 + 2。自从最近两天以来,我一直在为我的网站更新证书时发生此错误。续订letsencrypt证书失败
Could not bind TCP port 443 because it is already in use by another process on
this system (such as a web server). Please stop the program in question and then
try again.
-------------------------------------------------------------------------------
Attempting to renew cert from /etc/letsencrypt/renewal/www.testsite.com.conf produced an unexpected error: object of type 'NoneType' has no len(). Skipping.
我该怎么办?我对Letsencrypt并不熟悉。任何人都请在这个灯上点灯?