I configured the Atlas version 2.2.0 on AWS EMR, and did a basic search without prior importing the data in atlas, but it gives me the invalid expression error (in popup). What could be the possible reasons for that?
You haven't imported any metadata yet — so Atlas has no entity types or instances to search. The Basic Search UI tries to run a default query with an empty or invalid typeName, which leads to the “Invalid expression” popup.