No plugin exists with the handle "contact-form-extensions" I have installed and used the Contact Form Extensions plugin a few times but this time it's not working. I can see it in the CP but when I click to install it throws the error:


  Invalid plugin – craft\errors\InvalidPluginException
  'No plugin exists with the handle "contact-form-extensions".' 


When I install it the command line does say something about Carbon 1 being deprecated but not sure if it's related?
Try running ./craft project-config/rebuild from your terminal.