Login EM Express ask for user name and password

Hi! Out client have installed Oracle DB 12c (12.2.0.1) which will be used for restoring data from an existing Oracle 10g located in the same machine. When setting up the DB, the EM Express port was using default port 5500. We executed "exec dbms_xdb_config.SetGlobalPortEnabled(TRUE)" and able to login EM Express to both CDB and PDB. Later we found that the Oracle 10g also enabled port 5500 as EM Express but not always enabled. So we change the 12c EM Express port to 5502 to avoid conflict. After that, we found that we can login EM Express to PDB but browser