Apache: AH02240: Server should be SSL-aware but has no certificate configured / SSLCertificateFile: file '/etc/ssl/x.crt' does not exist or is empty

certificate does not have a private key (IIS) Windows/IIS: A specified logon session does not exist / The certificate does not have a private key associated with it Certificate pinning failure! Android/OkHttp: javax.net.ssl.SSLPeerUnverifiedException: Certificate pinning failure! Peer certificate chain: sha256/... Pinned certificates for api.example.com Cloudflare Origin CA not trusted NET::ERR_CERT_AUTHORITY_INVALID with a Cloudflare Origin Certificate (record not proxied) Could not establish trust relationship for the SSL/TLS secure channel .NET: System.Net.WebException: The underlying connection was closed: Could not establish trust relationship for the SSL/TLS secure channel DEPTH_ZERO_SELF_SIGNED_CERT Node/OpenSSL: Error: self signed certificate (code: DEPTH_ZERO_SELF_SIGNED_CERT) ERR_HTTP2_INADEQUATE_TRANSPORT_SECURITY Chrome: ERR_HTTP2_INADEQUATE_TRANSPORT_SECURITY — HTTP/2 requires a modern TLS cipher ERR_SSL_KEY_USAGE_INCOMPATIBLE Chrome: ERR_SSL_KEY_USAGE_INCOMPATIBLE — the certificate's key usage doesn't allow the negotiated cipher ERR_SSL_VERSION_OR_CIPHER_MISMATCH (Cloudflare) ERR_SSL_VERSION_OR_CIPHER_MISMATCH on a Cloudflare site (certificate not issued / multi-level subdomain) ERR_TOO_MANY_REDIRECTS (Cloudflare) ERR_TOO_MANY_REDIRECTS with Cloudflare (Flexible SSL redirect loop) HTTPSConnectionPool: Max retries exceeded (SSLError) Python requests: HTTPSConnectionPool(host='api.example.com', port=443): Max retries exceeded with url: /v1 (Caused by SSLError(SSLCertVerificationError(1, '[SSL: CERTIFICATE_VERIFY_FAILED] ...'))) incomplete certificate chain SSL Labs: Chain issues: Incomplete — Extra download (intermediate certificate missing) Invalid response from .well-known/acme-challenge: 404 Certbot: Detail: Invalid response from http://example.com/.well-known/acme-challenge/abc: 404 MySQL: SSL connection error: SSL is required but the server doesn't support it MySQL: ERROR 2026 (HY000): SSL connection error: SSL is required but the server doesn't support it no "ssl_certificate" is defined for the "listen ... ssl" directive Nginx: [emerg] no "ssl_certificate" is defined for the "listen ... ssl" directive in /etc/nginx/sites-enabled/default:3 NSURLErrorServerCertificateUntrusted (-1202) iOS: Error Domain=NSURLErrorDomain Code=-1202 "The certificate for this server is invalid. You might be connecting to a server that is pretending to be 'example.com'" root certificate file "root.crt" does not exist PostgreSQL: root certificate file "/home/user/.postgresql/root.crt" does not exist. Either provide the file or change sslmode SSL_CTX_use_PrivateKey_file failed (key values mismatch) Nginx: [emerg] SSL_CTX_use_PrivateKey_file("/etc/ssl/server.key") failed (SSL: error:0B080074:x509 certificate routines:X509_check_private_key:key values mismatch) Timeout during connect (likely firewall problem) Let's Encrypt: Fetching http://example.com/.well-known/acme-challenge/token: Timeout during connect (likely firewall problem) too many certificates already issued Let's Encrypt: urn:ietf:params:acme:error:rateLimited :: too many certificates (5) already issued for this exact set of identifiers in the last 168 hours unable to load Private Key OpenSSL/Nginx/Apache: error:0909006C:PEM routines:get_name:no start line / unable to load Private Key UNABLE_TO_VERIFY_LEAF_SIGNATURE Node.js: Error: unable to verify the first certificate (code: UNABLE_TO_VERIFY_LEAF_SIGNATURE) wildcard certificate does not cover a.b.example.com Browser: *.example.com certificate does not match a.b.example.com (ERR_CERT_COMMON_NAME_INVALID)