subscription-manager register command fails with error "NoMethodError: undefined method `first' for nil:NilClass"

Issue

• subscription-manager register command fails with error NoMethodError: undefined methodfirst' for nil:NilClass`

# subscription-manager register --org="Default_Organization" --activationkey="default-ak"
Task 752a773e-6d7e-45d6-8be6-59d22b556fdf: NoMethodError: undefined method `first' for nil:NilClass

• subscription-manager register command with following error

# subscription-manager register --org="Default_Organization" --activationkey="default-ak"
Runtime Error RESTEASY001185: Could not find resource for relative : /consumers//entitlements of full path: https://localhost:8443/candlepin/consumers//entitlements at org.jboss.resteasy.core.registry.PathParamSegment.matchPattern:209

• Deleting a host using hammer command fails with following error

# hammer host delete --name client.example.com
Could not delete the host:
  Katello::Resources::Candlepin::CandlepinResource: 404 Resource Not Found {"displayMessage":"Runtime Error RESTEASY001185: Could not find resource for relative : /consumers//entitlements of full path: https://localhost:8443/candlepin/consumers//entitlements at org.jboss.resteasy.core.registry.PathParamSegment.matchPattern:209","requestUuid":"decf501c-9b2e-403a-b0f3-c919a1f58ec6"} (GET /candlepin/consumers//entitlements)