環境
OS Name Microsoft Windows 10 Enterprise
Python 3.8.3
pip 20.1.1
今日の日付 2020-10-8

会社のパソコンで pip で Python パッケージをインストールしたら、

There was a problem confirming the ssl certificate
というエラーが出てしまいました。

pip install --trusted-host pypi.org --trusted-host files.pythonhosted.org analytics-mayhem-adobe
のように、したら、無事にパッケージをインストールできました。

エラー全文
Could not fetch URL https://pypi.org/simple/analytics-mayhem-adobe/: There was a problem confirming the ssl certificate: HTTPSConnectionPool(host='pypi.org', port=443): Max retries exceeded with url: /simple/analytics-mayhem-adobe/ (Caused by SSLError(SSLCertVerificationError(1, '[SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: unable to get local issuer certificate (_ssl.c:1108)'))) - skipping
ERROR: Could not find a version that satisfies the requirement analytics-mayhem-adobe (from versions: none)
ERROR: No matching distribution found for analytics-mayhem-adobe
Could not fetch URL https://pypi.org/simple/pip/: There was a problem confirming the ssl certificate: HTTPSConnectionPool(host='pypi.org', port=443): Max retries exceeded with url: /simple/pip/ (Caused by SSLError(SSLCertVerificationError(1, '[SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: unable to get local issuer certificate (_ssl.c:1108)'))) - skipping