500 Internal Server Error

Internal Server Error

Undefined variable $content

[tmp/1885hf6pp9swy.1vepkf0ajvep4.php:16] 
[tmp/1885hf6pp9swy.1vepkf0ajvep4.php:16] Base->{closure}()
[vendor/bcosca/fatfree-core/base.php:2955] require()
[vendor/bcosca/fatfree-core/base.php:3200] View->sandbox()
[app/controllers/controller.php:33] Preview->render()
[vendor/bcosca/fatfree-core/base.php:2003] Controller->afterroute()
[vendor/bcosca/fatfree-core/base.php:1795] Base->call()
[index.php:379] Base->run()