cloudinary can't find config items (api_key)

Question

Hi I am using cloudinary in my ROR 5.2 app and it was uploading fine but I had to remove cloudinary gem from my gem file and after removing it I rand bundle install command after that it stopped working and is giving me the following error

ActiveStorage::IntegrityError in Devise::RegistrationsController#create
Must supply api_key

My all other configurations are same and I haven't changed anything and I have also tried installing it again by using command gem install cloudinary but I am getting same error. Note https://medium.com/nerd-for-tech/getting-started-with-cloudinary-in-ruby-on-rails-6-925888032395

I followed above mentioned tutorial.