See below warning message dated 28 Nov 2021 10:31am HK Time
SSLError: HTTPSConnectionPool(host='bern.korea.ac.kr', port=443): Max retries exceeded with url: /plain (Caused by SSLError(SSLCertVerificationError(1, '[SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: certificate has expired (_ssl.c:1129)')))