It seems that you might experience the one of the following scenario:

• check if you are on the correct GCP project, Dialogflow ES must be tied to a specific GCP project. To check, go to your console and look for that project you're working on.

• also, double check if it’s really Dialogflow ES, Dialogflow CX and ES are different that's why you can not see your conversational agent. You might want to check also if you are still on the IAM and Admin access that might be restricting you.