Mollie – Fatal error after activation

I tried delete and re-install but mollie gives fatal error. Any idea please?

Fatal error: Uncaught Error: Call to undefined function GuzzleHttp\Promise\promise_for() in /var/www/vhosts/transstock.eu/httpdocs/wp-content/plugins/stonehenge-em-mollie/vendor/guzzlehttp/guzzle/src/Client.php:323 Stack trace: #0 /var/www/vhosts/transstock.eu/httpdocs/wp-content/plugins/stonehenge-em-mollie/vendor/guzzlehttp/guzzle/src/Client.php(101): GuzzleHttp\Client->transfer() #1 /var/www/vhosts/transstock.eu/httpdocs/wp-content/plugins/stonehenge-em-mollie/vendor/guzzlehttp/guzzle/src/Client.php(117): GuzzleHttp\Client->sendAsync() #2 /var/www/vhosts/transstock.eu/httpdocs/wp-content/plugins/stonehenge-em-mollie/vendor/mollie/mollie-api-php/src/MollieApiClient.php(461): GuzzleHttp\Client->send() #3 /var/www/vhosts/transstock.eu/httpdocs/wp-content/plugins/stonehenge-em-mollie/vendor/mollie/mollie-api-php/src/MollieApiClient.php(418): Mollie\Api\MollieApiClient->performHttpCallToFullUrl() #4 /var/www/vhosts/transstock.eu/httpdocs/wp-content/plugins/stonehenge-em-mollie/vendor/mollie/mollie-api-php/src/Endpoints/Endp in /var/www/vhosts/transstock.eu/httpdocs/wp-content/plugins/stonehenge-em-mollie/vendor/guzzlehttp/guzzle/src/Client.php on line 323