google-cloud-ruby: Google Cloud PubSub async pull returns GRPC::DeadlineExceeded error

Hi, not sure if this is a bug or an error on my part. I have a subscription set up in Google PubSub and I am trying to pull messages asynchronously using the google-cloud-ruby library. Here is my code which will be executed from a rake task which passes in subscription_name:

def pull!
  creds = Google::Cloud::PubSub::Credentials.new(
    GCP_CREDENTIALS_KEYFILE_PATH,
    scope: "https://www.googleapis.com/auth/pubsub"
  )
  messages = []
  pubsub = Google::Cloud::PubSub.new(
    project_id: GOOGLE_PROJECT_ID,
    credentials: creds
  )

  subscription = pubsub.subscription(subscription_name)

  subscription.pull(immediate: true).each do |received_message|
    puts "Received message: #{received_message.data}"
    received_message.acknowledge!
    messages.push(received_message)
  end

  # Return the collected messages
  messages
  
rescue => error
  Rails.logger error

  messages.presence
end

The Google::Cloud::PubSub::Credentials part references a working keyfile. I know the JSON keyfile is good since I can use it to generate a working Bearer token using oauth2l and pull from the PubSub using cURL, postman, Net::HTTP, etc. Using an identical JSON credentials object for a separate Google::Cloud::Storage service and that works fine also.

But for some reason using Google::Cloud::PubSub it just hangs and won’t respond. After about 60 seconds I get the following error:

GRPC::DeadlineExceeded: 4:Deadline Exceeded. debug_error_string:{"created":"@1602610740.445195000","description":"Deadline Exceeded","file":"src/core/ext/filters/deadline/deadline_filter.cc","file_line":69,"grpc_status":4}
/Users/bbulpet/.rbenv/versions/2.6.5/lib/ruby/gems/2.6.0/gems/grpc-1.32.0-universal-darwin/src/ruby/lib/grpc/generic/active_call.rb:29:in `check_status'
/Users/bbulpet/.rbenv/versions/2.6.5/lib/ruby/gems/2.6.0/gems/grpc-1.32.0-universal-darwin/src/ruby/lib/grpc/generic/active_call.rb:180:in `attach_status_results_and_complete_call'
/Users/bbulpet/.rbenv/versions/2.6.5/lib/ruby/gems/2.6.0/gems/grpc-1.32.0-universal-darwin/src/ruby/lib/grpc/generic/active_call.rb:376:in `request_response'
/Users/bbulpet/.rbenv/versions/2.6.5/lib/ruby/gems/2.6.0/gems/grpc-1.32.0-universal-darwin/src/ruby/lib/grpc/generic/client_stub.rb:172:in `block (2 levels) in request_response'
/Users/bbulpet/.rbenv/versions/2.6.5/lib/ruby/gems/2.6.0/gems/grpc-1.32.0-universal-darwin/src/ruby/lib/grpc/generic/interceptors.rb:170:in `intercept!'
/Users/bbulpet/.rbenv/versions/2.6.5/lib/ruby/gems/2.6.0/gems/grpc-1.32.0-universal-darwin/src/ruby/lib/grpc/generic/client_stub.rb:171:in `block in request_response'
/Users/bbulpet/.rbenv/versions/2.6.5/lib/ruby/gems/2.6.0/gems/gapic-common-0.3.4/lib/gapic/grpc/service_stub/rpc_call.rb:121:in `call'
/Users/bbulpet/.rbenv/versions/2.6.5/lib/ruby/gems/2.6.0/gems/gapic-common-0.3.4/lib/gapic/grpc/service_stub.rb:156:in `call_rpc'
/Users/bbulpet/.rbenv/versions/2.6.5/lib/ruby/gems/2.6.0/gems/google-cloud-pubsub-v1-0.1.2/lib/google/cloud/pubsub/v1/subscriber/client.rb:503:in `get_subscription'
/Users/bbulpet/.rbenv/versions/2.6.5/lib/ruby/gems/2.6.0/gems/google-cloud-pubsub-2.1.0/lib/google/cloud/pubsub/service.rb:154:in `get_subscription'
/Users/bbulpet/.rbenv/versions/2.6.5/lib/ruby/gems/2.6.0/gems/google-cloud-pubsub-2.1.0/lib/google/cloud/pubsub/project.rb:286:in `subscription'

I’ve tried everything I can think of based on the documentation. Updated all related gems and even tried using deprecated syntax out of desperation. When a debugger is added it appears that this occurs when the following call is executed:

pubsub.subscription(subscription_name)

Also I know the above code does work to produce a Google::Cloud::PubSub::Project object (which I’ve assigned to pubsub variable), but calling any method of pubsub hangs for a minute and throws the above error response.

If anyone has at least an idea of where to start troubleshooting that would be most appreciated. Curious to know if there are known issues or potential conflicts with other Google::Cloud gems/dependencies (this project does use google-cloud-storage as well).

Thanks