Login is current disabled under Kibana UI

curl -uelastic:test123 "100.98.26.181:9200/"
{"error":{"root_cause":[{"type":"security_exception","reason":"failed to authenticate user [elastic]","header":{"WWW-Authenticate":"Basic realm=\"security\" charset=\"UTF-8\""}}],"type":"security_exception","reason":"failed to authenticate user [elastic]","header":{"WWW-Authenticate":"Basic realm=\"security\" charset=\"UTF-8\""}},"status":401}

May I know how does one setup username and password?
I mean how does this authenticate to? All I have been putting .env file where I pass ELASTIC_PASSWORD variable with password and when I try passing it drectly as shown above, it just fails to connect with 401 error.