Fatal error: Uncaught Exception: GMP extension seems not to be installed in C:\inetpub\wwwroot\bitcoin\vendor\bitcoin-php\bitcoin-ecdsa\src\BitcoinPHP\BitcoinECDSA\BitcoinECDSA.php:11 Stack trace: #0 C:\inetpub\wwwroot\bitcoin\vendor\composer\ClassLoader.php(444): include() #1 C:\inetpub\wwwroot\bitcoin\vendor\composer\ClassLoader.php(322): Composer\Autoload\includeFile('C:\\inetpub\\wwwr...') #2 [internal function]: Composer\Autoload\ClassLoader->loadClass('BitcoinPHP\\Bitc...') #3 C:\inetpub\wwwroot\bitcoin\index.php(9): spl_autoload_call('BitcoinPHP\\Bitc...') #4 {main} thrown in C:\inetpub\wwwroot\bitcoin\vendor\bitcoin-php\bitcoin-ecdsa\src\BitcoinPHP\BitcoinECDSA\BitcoinECDSA.php on line 11