Slim Application Error

The application could not run because of the following error:

Details

Type: ErrorException
Code: 2
Message: virtual(): Session ini settings cannot be changed when a session is active (started from /virtual/htdocs/alice/contact/index.php on line 12)
File: /virtual/htdocs/alice/contact/template/form.php
Line: 21

Trace

#0 [internal function]: Slim\Slim::handleErrors()
#1 /virtual/htdocs/alice/contact/template/form.php(21): virtual()
#2 /virtual/htdocs/alice/contact/formApp/third_party/Slim/View.php(278): require(&
#039;...&
#039;)
#3 /virtual/htdocs/alice/contact/formApp/third_party/Slim/View.php(255): Slim\View->render()
#4 /virtual/htdocs/alice/contact/formApp/third_party/Slim/View.php(243): Slim\View->fetch()
#5 /virtual/htdocs/alice/contact/formApp/Controller/Contactform.php(12): Slim\View->display()
#6 [internal function]: {closure:/virtual/htdocs/alice/contact/formApp/Controller/Contactform.php:7}()
#7 /virtual/htdocs/alice/contact/formApp/third_party/Slim/Route.php(468): call_user_func_array()
#8 /virtual/htdocs/alice/contact/formApp/third_party/Slim/Slim.php(1357): Slim\Route->dispatch()
#9 /virtual/htdocs/alice/contact/formApp/third_party/Slim/Middleware/Flash.php(85): Slim\Slim->call()
#10 /virtual/htdocs/alice/contact/formApp/third_party/Slim/Middleware/MethodOverride.php(92): Slim\Middleware\Flash->call()
#11 /virtual/htdocs/alice/contact/formApp/third_party/Slim/Middleware/PrettyExceptions.php(67): Slim\Middleware\MethodOverride->call()
#12 /virtual/htdocs/alice/contact/formApp/third_party/Slim/Slim.php(1302): Slim\Middleware\PrettyExceptions->call()
#13 /virtual/htdocs/alice/contact/index.php(38): Slim\Slim->run()
#14 {main}