問題：
服務器已經使用Certbot配置過SSL，現在需要給一個新增域名配置SSL，再次執行./certbot-auto --nginx --no-bootstrap 時出現以下錯誤：
Collecting certbot==0.22.0 (from -r /tmp/tmp.azB9bqXOOL/letsencrypt-auto-requirements.txt (line 206)) Could not find a version that satisfies the requirement certbot==0.22.0 (from -r /tmp/tmp.azB9bqXOOL/letsencrypt-auto-requirements.txt (line 206)) (from versions: 0.6.0, 0.7.0, 0.8.0, 0.8.1, 0.9.0, 0.9.1, 0.9.2, 0.9.3, 0.10.0, 0.10.1, 0.10.2, 0.11.0, 0.11.1, 0.12.0, 0.13.0, 0.14.0, 0.14.1, 0.14.2, 0.15.0, 0.16.0, 0.17.0, 0.18.0, 0.18.1, 0.18.2, 0.19.0, 0.20.0, 0.21.0, 0.21.1) No matching distribution found for certbot==0.22.0 (from -r /tmp/tmp.azB9bqXOOL/letsencrypt-auto-requirements.txt (line 206)) ===================================================== Certbot has problem setting up the virtual environment. We were not be able to guess the right solution from your pip output. Consult https://certbot.eff.org/docs/install.html#problems-with-python-virtual-environment for possible solutions. You may also find some support resources at https://certbot.eff.org/support/ .
由於本人對pip配置環境還不熟悉，查找了github上Issues發現這是過時的pip配置引起的，只需要在用戶目錄下面刪除.pip/pip.conf即可，目前已經配置成功！
參考：
https://github.com/certbot/certbot/issues/4309