I have similar problem with WordPress 4.9.7. But it is working for all intent hosted on dialogflow except the one which are fulfilled through webhook using Google Cloud service. The error in the Firebase server log is as below.
TypeError: Cannot read property
‘isInSandbox’
of undefined
at DialogflowConversation.Conversation (/user_code/node_modules/actions-on-google/dist/service/actionssdk/conversation/conversation.js:37:38)
at DialogflowConversation (/user_code/node_modules/actions-on-google/dist/service/dialogflow/conv.js:27:9)
at Function.<anonymous> (/user_code/node_modules/actions-on-google/dist/service/dialogflow/dialogflow.js:87:24)
at next (native)
at /user_code/node_modules/actions-on-google/dist/service/dialogflow/dialogflow.js:22:71
at __awaiter (/user_code/node_modules/actions-on-google/dist/service/dialogflow/dialogflow.js:18:12)
at Function.handler (/user_code/node_modules/actions-on-google/dist/service/dialogflow/dialogflow.js:58:16)
at Object.<anonymous> (/user_code/node_modules/actions-on-google/dist/assistant.js:53:32)
at next (native)
at /user_code/node_modules/actions-on-google/dist/assistant.js:22:71
And this same intent is working fine and retrieving information from Google Cloud through Google Assistant and Skype.
I am using V2 API as suggested by Dialogflow and I could see ‘isInSandbox’ being used in deprecated V1 API. Please suggest whether Chatbot is using V1 or V2 API or both are Ok.