0x800c0019 = SEC_E_CHANNEL_ERROR (0x800C0019) From winerror.h :
TLS 1.2 is enabled by default. If disabled by policy, re-enable via: net framework download failed with error code 0x800c0019
Here is the technical content explaining during .NET Framework installation, followed by a troubleshooting guide you can use directly or adapt for support documentation. Error Overview Error Code: 0x800c0019 Common Translation: ERROR_INTERNET_SECURITY_CHANNEL_ERROR Typical Message: "The .NET Framework download failed" or "A security error occurred while processing the download" What the Error Means This error indicates a failure in the Secure Channel (Schannel) – the component responsible for establishing HTTPS (TLS/SSL) connections. The client and server could not negotiate a secure connection due to mismatched or unsupported security protocols, ciphers, or certificates. 0x800c0019 = SEC_E_CHANNEL_ERROR (0x800C0019) From winerror
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\WinHttp] "DefaultSecureProtocols"=dword:00000a00 [HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Windows\CurrentVersion\Internet Settings\WinHttp] "DefaultSecureProtocols"=dword:00000a00 net framework download failed with error code 0x800c0019