What is "agent" in Consul?

I have a Vault installed Kubernetes and its storage backend is Consul.
In order secure Consul access I enabled ACL in Consul but now Vault cannot access to Consul. I haven’t found any documentation which explains this scenario.

How can I fix that problem? Could you please advise?

Thanks & Regards

In consul you don’t talk to the server(s). You talk to the data layer, these are the “agents” that do the service registration, request proxies, update data, etc…