Make sure annotations are installed and enabled, how to solve?

Question

symfony

Symfony 3.3

{"error":{"code":0,"message":"Class AppBundle\\Controller\\Airport1Controller does not exist in \/var\/www\/html\/src\/AppBundle\/Controller\ / (which is being imported from \u0022\/var\/www\/html\/app\/config\/routing.yml\u0022). Make sure annotations are installed and enabled."},"data":[] }