failed to start ASMB (connection failed) ora-01017: invalid username/password; logon denied

Error:

Whenever I try to create a new database using DBCA or duplicate a database to a newly installed 19c (19.5) server with ASM I was getting the following errors in the alertlog:

WARNING: failed to start ASMB (connection failed) state=0x1 sid='+ASM'
2021-07-04T09:58:15.869920+00:00
Errors in file /u01/oracle/diag/rdbms/sps/sps/trace/sps_asmb_4765.trc:
ORA-01017: invalid username/password; logon denied
Stopping background process RBAL
2021-07-04T09:58:16.870779+00:00
WARNING: ASMB exiting with error
 

Analysis:

oracle user must have oinstall as its primary group, in my setup it was mistakenly assigned as a secondary group rather than primary group.

Solution:

Make oinstall the primary group for Oracle user:

# usermod -g oinstall oracle