UNABLE TO CONNECT TO DATABSE!

Fatal error: Uncaught RuntimeException: PDOException: SQLSTATE[08006] [7] connection to server at "polymart-dev-new.cmorpn4dsujc.us-east-1.rds.amazonaws.com" (172.31.64.47), port 5432 failed: FATAL: sorry, too many clients already connection to server at "polymart-dev-new.cmorpn4dsujc.us-east-1.rds.amazonaws.com" (172.31.64.47), port 5432 failed: FATAL: sorry, too many clients already in /var/www/html/polymart/utils/Doco.php:141 Stack trace: #0 /var/www/html/polymart/utils/Doco.php(141): PDO->__construct() #1 /var/www/html/polymart/utils/Doco.php(357): Doco\newConnection() #2 /var/www/html/polymart/utils/Doco.php(562): Doco\makeFetch() #3 /var/www/html/polymart/utils/WebUtils.php(15): Doco\fetchAll() #4 /var/www/html/polymart/web/pages/product/search.php(5): include_once('...') #5 {main} in /var/www/html/polymart/utils/Doco.php:173 Stack trace: #0 /var/www/html/polymart/utils/Doco.php(357): Doco\newConnection() #1 /var/www/html/polymart/utils/Doco.php(562): Doco\makeFetch() #2 /var/www/html/polymart/utils/WebUtils.php(15): Doco\fetchAll() #3 /var/www/html/polymart/web/pages/product/search.php(5): include_once('...') #4 {main} thrown in /var/www/html/polymart/utils/Doco.php on line 173