Enterprise Manager Base Platform - Version 12.1.0.5 error

Enterprise Manager Base Platform - Version 12.1.0.5 version when I click  manager Server

then

java.lang.IllegalStateException: No central agents of the management servers could be obtained for plugin deployment. The following query was used to retrieve them - "SELECT t.target_name, t.emd_url, op.host_url, op.oms_id, op.status, op.unique_oms_name, op.is_first_oms, op.oracle_home, op.server_name, op.domain_name, t.host_name , ca.current_status FROM gc_oms_info op, mgmt_targets t , mgmt_current_availability ca WHERE op.host_name = t.host_name AND op.em_release_version = ? AND op.domain_name = ? AND t.target_type='oracle_emd' AND ca.target_guid = t.target_guid ORDER BY op.oms_id"