captcha not loading image

[amishdotcom]

captcha is suddenly not loading the image

Error log :

[07-May-2018 09:27:52 Europe/Berlin] PHP Fatal error: Uncaught Error: Call to undefined function imagecreate() in /var/www/blivu.com/public_html/objects/captcha.php:23
Stack trace:
#0 /var/www/blivu.com/public_html/objects/getCaptcha.php(10): Captcha->getCaptchaImage()
#1 {main}
thrown in /var/www/blivu.com/public_html/objects/captcha.php on line 23
[07-May-2018 09:27:55 Europe/Berlin] PHP Fatal error: Uncaught Error: Call to undefined function imagecreate() in /var/www/blivu.com/public_html/objects/captcha.php:23
Stack trace:
#0 /var/www/blivu.com/public_html/objects/getCaptcha.php(10): Captcha->getCaptchaImage()
#1 {main}
thrown in /var/www/blivu.com/public_html/objects/captcha.php on line 23
[07-May-2018 09:27:56 Europe/Berlin] PHP Fatal error: Uncaught Error: Call to undefined function imagecreate() in /var/www/blivu.com/public_html/objects/captcha.php:23
Stack trace:
#0 /var/www/blivu.com/public_html/objects/getCaptcha.php(10): Captcha->getCaptchaImage()
#1 {main}
thrown in /var/www/blivu.com/public_html/objects/captcha.php on line 23
[07-May-2018 09:27:58 Europe/Berlin] PHP Fatal error: Uncaught Error: Call to undefined function imagecreate() in /var/www/blivu.com/public_html/objects/captcha.php:23
Stack trace:
#0 /var/www/blivu.com/public_html/objects/getCaptcha.php(10): Captcha->getCaptchaImage()
#1 {main}
thrown in /var/www/blivu.com/public_html/objects/captcha.php on line 23
[07-May-2018 09:28:07 Europe/Berlin] PHP Fatal error: Uncaught Error: Call to undefined function imagecreate() in /var/www/blivu.com/public_html/objects/captcha.php:23
Stack trace:
#0 /var/www/blivu.com/public_html/objects/getCaptcha.php(10): Captcha->getCaptchaImage()
#1 {main}
thrown in /var/www/blivu.com/public_html/objects/captcha.php on line 23
[07-May-2018 09:28:10 Europe/Berlin] PHP Fatal error: Uncaught Error: Call to undefined function imagecreate() in /var/www/blivu.com/public_html/objects/captcha.php:23
Stack trace:
#0 /var/www/blivu.com/public_html/objects/getCaptcha.php(10): Captcha->getCaptchaImage()
#1 {main}
thrown in /var/www/blivu.com/public_html/objects/captcha.php on line 23
[07-May-2018 09:30:57 Europe/Berlin] PHP Fatal error: Uncaught Error: Call to undefined function imagecreate() in /var/www/blivu.com/public_html/objects/captcha.php:23
Stack trace:
#0 /var/www/blivu.com/public_html/objects/getCaptcha.php(10): Captcha->getCaptchaImage()
#1 {main}
thrown in /var/www/blivu.com/public_html/objects/captcha.php on line 23

[amishdotcom]

I solved the issue, found that gd library wasn't installed