Operating System:
Windows Server 2012 R2
IIS

Error Message:
The Composer installer script was not successful [exit code 1].

Script Output:
The "https://getcomposer.org/versions" file could not be downloaded: failed to open stream: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond.

Log file:

2019-02-19 08:19:27.618 Log opened. (Time zone: UTC+01:00)
2019-02-19 08:19:27.618 Setup version: Inno Setup version 5.6.1 (u)
2019-02-19 08:19:27.618 Original Setup EXE: C:\Distrib\Composer-Setup.exe
2019-02-19 08:19:27.618 Setup command line: /SL5="$20354,282297,121344,C:\Distrib\Composer-Setup.exe" /SPAWNWND=$10314 /NOTIFYWND=$20304
2019-02-19 08:19:27.618 Windows version: 6.3.9600 (NT platform: Yes)
2019-02-19 08:19:27.618 64-bit Windows: Yes
2019-02-19 08:19:27.618 Processor architecture: x64
2019-02-19 08:19:27.618 User privileges: Administrative
2019-02-19 08:19:27.618 64-bit install mode: No
2019-02-19 08:19:27.633 Created temporary directory: C:\Users\RUBLIN1\AppData\Local\Temp\is-9V1FA.tmp
2019-02-19 08:19:27.633 -- DLL function import --
2019-02-19 08:19:27.633 Function name: SetEnvironmentVariableW
2019-02-19 08:19:27.633 DLL name: kernel32.dll
2019-02-19 08:19:27.633 Dest DLL name: kernel32.dll
2019-02-19 08:19:27.633 Importing the DLL function.
2019-02-19 08:19:27.633 Successfully imported the DLL function. Delay loaded? Yes
2019-02-19 08:19:27.633 -- DLL function import --
2019-02-19 08:19:27.633 Function name: ExpandEnvironmentStringsW
2019-02-19 08:19:27.633 DLL name: kernel32.dll
2019-02-19 08:19:27.633 Dest DLL name: kernel32.dll
2019-02-19 08:19:27.633 Importing the DLL function.
2019-02-19 08:19:27.633 Successfully imported the DLL function. Delay loaded? Yes
2019-02-19 08:19:27.633 -- DLL function import --
2019-02-19 08:19:27.633 Function name: SendMessageTimeoutW
2019-02-19 08:19:27.633 DLL name: user32.dll
2019-02-19 08:19:27.633 Dest DLL name: user32.dll
2019-02-19 08:19:27.633 Importing the DLL function.
2019-02-19 08:19:27.633 Successfully imported the DLL function. Delay loaded? Yes
2019-02-19 08:19:27.633 -- DLL function import --
2019-02-19 08:19:27.633 Function name: DeleteData
2019-02-19 08:19:27.633 DLL name: uninstall:{app}\userdata.dll
2019-02-19 08:19:27.633 Skipping.
2019-02-19 08:19:27.633 -- DLL function import --
2019-02-19 08:19:27.633 Function name: GetResult
2019-02-19 08:19:27.633 DLL name: uninstall:{app}\userdata.dll
2019-02-19 08:19:27.633 Skipping.
2019-02-19 08:19:27.633 Extracting temporary file: C:\Users\RUBLIN1\AppData\Local\Temp\is-9V1FA.tmp\runphp.exe
2019-02-19 08:19:27.664 Extracting temporary file: C:\Users\RUBLIN1\AppData\Local\Temp\is-9V1FA.tmp\check.php
2019-02-19 08:19:27.664 Extracting temporary file: C:\Users\RUBLIN1\AppData\Local\Temp\is-9V1FA.tmp\installer.php
2019-02-19 08:19:27.696 Extracting temporary file: C:\Users\RUBLIN1\AppData\Local\Temp\is-9V1FA.tmp\ini.php
2019-02-19 08:19:27.696 Extracting temporary file: C:\Users\RUBLIN1\AppData\Local\Temp\is-9V1FA.tmp\composer
2019-02-19 08:19:27.696 $ Initializing ComposerSetup 4.10.0 for user: RUBLINOVD
2019-02-19 08:19:27.696 $ Getting path info from registry
2019-02-19 08:19:27.868 $ WizardPage [001]: Welcome
2019-02-19 08:19:27.868 $ WizardPage [100]: Installation Options
2019-02-19 08:25:52.588 $ WizardPage [101]: Settings Check
2019-02-19 08:25:53.678 $ WizardPage [102]: Running Settings Check
2019-02-19 08:25:53.678 $ Checking selected php: C:\Program Files\php\v7.1\php.exe
2019-02-19 08:25:53.678 $ Env: PHPRC=, PHP_INI_SCAN_DIR=
2019-02-19 08:25:53.678 $ Reading VersionInfo data from exe
2019-02-19 08:25:53.678 $ Config: version=7.1.7, id=70107
2019-02-19 08:25:53.678 $ Checking if php will execute
2019-02-19 08:25:53.678 $ -- Execute File --
2019-02-19 08:25:53.678 $ Running C:\Users\RUBLIN1\AppData\Local\Temp\is-9V1FA.tmp\runphp.exe "C:\Program Files\php\v7.1\php.exe"
2019-02-19 08:25:53.881 $ Success: exit code [0]
2019-02-19 08:25:53.881 $ Checking php configuration
2019-02-19 08:25:53.881 $ -- Execute File --
2019-02-19 08:25:53.881 $ Running C:\Windows\system32\cmd.exe /c ""C:\Program Files\php\v7.1\php.exe" -d error_reporting=E_ALL -d display_errors=Off -d display_startup_errors=Off -d error_log= -d log_errors=On check.php > C:\Users\RUBLIN1\AppData\Local\Temp\is-9V1FA.tmp\stdout.txt 2> C:\Users\RUBLIN1\AppData\Local\Temp\is-9V1FA.tmp\stderr.txt"
2019-02-19 08:25:54.084 $ Success: exit code [0]
2019-02-19 08:25:54.084 $ Output from stdout [67 bytes]
ComposerSetup:7.1.7|70107|C:\Program Files\php\v7.1\php.ini|1|||1
2019-02-19 08:25:54.084 $ Output from stderr [0 bytes]
2019-02-19 08:25:54.084 $ Config: version=7.1.7, id=70107, ini=C:\Program Files\php\v7.1\php.ini, tls=1, cafile=, capath=, compat=1
2019-02-19 08:25:54.084 $ PhpIni: Checking if ini needs updating: C:\Program Files\php\v7.1\php.ini
2019-02-19 08:25:54.100 $ -- Execute File --
2019-02-19 08:25:54.100 $ Running C:\Windows\system32\cmd.exe /c ""C:\Program Files\php\v7.1\php.exe" -d error_reporting=E_ALL -d display_errors=Off -d display_startup_errors=Off -d error_log= -d log_errors=On ini.php "C:\Program Files\php\v7.1" C:\Users\RUBLIN1\AppData\Local\Temp\is-9V1FA.tmp\php.ini C:\Users\RUBLIN1\AppData\Local\Temp\is-9V1FA.tmp\php.ini.backup > C:\Users\RUBLIN1\AppData\Local\Temp\is-9V1FA.tmp\stdout.txt 2> C:\Users\RUBLIN1\AppData\Local\Temp\is-9V1FA.tmp\stderr.txt"
2019-02-19 08:25:54.303 $ Success: exit code [0]
2019-02-19 08:25:54.303 $ Output from stdout [49 bytes]
ComposerSetup:0|No changes to ini file required
2019-02-19 08:25:54.303 $ Output from stderr [0 bytes]
2019-02-19 08:25:54.303 $ PhpIni: modify=0, status=No changes to ini file required
2019-02-19 08:25:54.303 $ Checking php path
2019-02-19 08:25:54.303 $ Checking composer bin path
2019-02-19 08:25:54.303 $ Registering: Add to System path: C:\ProgramData\ComposerSetup\bin
2019-02-19 08:25:54.303 $ Checking PathExt values for .BAT
2019-02-19 08:25:54.303 $ Registering: Add to User path: C:\Users\RUBLINOVD\AppData\Roaming\Composer\vendor\bin
2019-02-19 08:25:54.303 $ WizardPage [101]: Settings Check
2019-02-19 08:25:54.319 $ WizardPage [106]: Proxy Settings
2019-02-19 08:26:07.991 $ Registering: Add to User environment: http_proxy
2019-02-19 08:26:08.007 $ WizardPage [010]: Ready to Install
2019-02-19 08:26:08.793 $ WizardPage [107]: Running Composer Install
2019-02-19 08:26:08.793 $ Running Composer installer script
2019-02-19 08:26:08.793 $ Setting http_proxy local environment variable
2019-02-19 08:26:08.793 $ -- Execute File --
2019-02-19 08:26:08.793 $ Running C:\Windows\system32\cmd.exe /c ""C:\Program Files\php\v7.1\php.exe" -d error_reporting=E_ALL -d display_errors=Off -d display_startup_errors=Off -d error_log= -d log_errors=On installer.php -- --no-ansi --quiet > C:\Users\RUBLIN1\AppData\Local\Temp\is-9V1FA.tmp\stdout.txt 2> C:\Users\RUBLIN~1\AppData\Local\Temp\is-9V1FA.tmp\stderr.txt"
2019-02-19 08:27:12.274 $ Success: exit code [1]
2019-02-19 08:27:12.274 $ Output from stdout [275 bytes]
The "https://getcomposer.org/versions" file could not be downloaded: failed to open stream: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond.
2019-02-19 08:27:12.274 $ Output from stderr [0 bytes]
2019-02-19 08:27:12.274 $ Clearing http_proxy local environment variable
2019-02-19 08:27:12.274 $ Error: [ERR_INSTALL_ERRORS]
The Composer installer script was not successful [exit code 1].

                      Script Output:
                      The "https://getcomposer.org/versions" file could not be downloaded: failed to open stream: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond.

2019-02-19 08:27:12.274 $ WizardPage [010]: Ready to Install
2019-02-19 08:27:12.290 $ WizardPage [108]: Composer Install Errors