Fatal error: Uncaught Error: Interface 'JsonSerializable' not found in /home3/puntoeje/public_html/blockchain/nuevo/vendor/guzzlehttp/promises/tests/Thing2.php:7 Stack trace: #0 {main} thrown in /home3/puntoeje/public_html/blockchain/nuevo/vendor/guzzlehttp/promises/tests/Thing2.php on line 7