500 Internal Server Error

Undefined index: index (8)

#0 /home/u238729589/domains/eduplusapp.com/public_html/functions.php(58): flight\Engine->handleError(8, 'Undefined index...', '/home/u23872958...', 58, Array)
#1 /home/u238729589/domains/eduplusapp.com/public_html/index.php(56): _getPage('index')
#2 /home/u238729589/domains/eduplusapp.com/public_html/vendor/mikecao/flight/flight/core/Dispatcher.php(169): {closure}('index')
#3 /home/u238729589/domains/eduplusapp.com/public_html/vendor/mikecao/flight/flight/core/Dispatcher.php(145): flight\core\Dispatcher::callFunction(Object(Closure), Array)
#4 /home/u238729589/domains/eduplusapp.com/public_html/vendor/mikecao/flight/flight/Engine.php(342): flight\core\Dispatcher::execute(Object(Closure), Array)
#5 /home/u238729589/domains/eduplusapp.com/public_html/vendor/mikecao/flight/flight/core/Dispatcher.php(198): flight\Engine->_start()
#6 /home/u238729589/domains/eduplusapp.com/public_html/vendor/mikecao/flight/flight/core/Dispatcher.php(144): flight\core\Dispatcher::invokeMethod(Array, Array)
#7 /home/u238729589/domains/eduplusapp.com/public_html/vendor/mikecao/flight/flight/core/Dispatcher.php(49): flight\core\Dispatcher::execute(Array, Array)
#8 /home/u238729589/domains/eduplusapp.com/public_html/vendor/mikecao/flight/flight/Engine.php(92): flight\core\Dispatcher->run('start', Array)
#9 /home/u238729589/domains/eduplusapp.com/public_html/vendor/mikecao/flight/flight/core/Dispatcher.php(198): flight\Engine->__call('start', Array)
#10 /home/u238729589/domains/eduplusapp.com/public_html/vendor/mikecao/flight/flight/Flight.php(77): flight\core\Dispatcher::invokeMethod(Array, Array)
#11 /home/u238729589/domains/eduplusapp.com/public_html/index.php(89): Flight::__callStatic('start', Array)
#12 {main}