Access amazon managed Grfana dashboard using keycloak user (wittout EKS)

In a small ec2 instance in AWS account with private subnet have installed Keycloak and configure realm and client for AWS Grafana (SAML). With the help of Keycloak user we could not be able to access Grafana dashboard. Please help us to share the configuration without EKS. We do not have AWS-SSO access to create user. Need to configure SAML authentication using Keycloak user.
Error we are getting: “Failed to obtain required user information from the assertion, make sure assertion mapping is correct.”