Where to troubleshoot phpPgAdmin login issues?

I am getting "Login failed" errors when attempting to log into phpPgAdmin as user 'postgres'. In what file path would I find the relevant log files, to try and identify why the login is being rejected? OS: CentOS 7 PostgreSQL: 9.6.6 pg_hba.conf settings for access: # TYPE DATABASE USER ADDRESS METHOD # "local" is for Unix domain socket connections only local all all peer # IPv4 local connections: #host all all 127.0.0.1/32 ident #host all all 127.0.0.1/32 md5 host all all 192.168.101.1/32 md5 # IPv6 local connections: #host all all ::1/128 ident host all all ::1/128 md5 # Allow replication connections from localhost, by a user with the # replication privilege. #local replication postgres peer #host replication postgres 127.0.0.1/32 ident #host replication postgres ::1/128 ident