Oracle DBMS SCHEDULER - Email notification for job is not working

I am using Oracle version 11.2.0.1.0.

I have created job using dbms scheduler as below,

DECLARE
    v_job_name VARCHAR2(5) := SYS.DBMS_SCHEDULER.GENERATE_JOB_NAME(prefix =>  'JOB'); 
BEGIN
    SYS.DBMS_SCHEDULER.create_job(
        job_name            =>  v_job_name,
        job_type            =>  'PLSQL_BLOCK',
        job_action          =>  'PKG_TEST.PROCEDURE_TEST;',
        start_date          =>  SYSDATE,
        enabled             =>  TRUE,
        repeat_interval     =>  'freq=minutely; interval=2',
        auto_drop           =>  FALSE,
        comments            =>  'Scheduler Test'        
    );
    SYS.DBMS_OUTPUT.PUT_LINE('Job Name is: ' || v_job_name);
END;

Next, configured email notification and SMTP server for above job as below,

EXEC SYS.dbms_scheduler.set_scheduler_attribute('email_server','XXXX.office365.com:XXX');
/
EXEC SYS.dbms_scheduler.set_scheduler_attribute('email_server_encryption','XXXXXX');
/
EXEC SYS.DBMS_SCHEDULER.create_credential (credential_name  => 'MAILSERVER_CREDENTIAL',
                                                username        => 'XXXXX@XXXXXX.com',
                                                password        => 'XXXXXX');
/
EXEC SYS.dbms_scheduler.set_scheduler_attribute('email_server_credential','MAILSERVER_CREDENTIAL');
/
EXEC SYS.DBMS_SCHEDULER.ADD_JOB_EMAIL_NOTIFICATION (
    job_name            =>  'JOB52',
    recipients          =>  'XXXXX@XXXXX.com',
    sender              =>  'XXXXX@XXXX.com.XX',
    subject             =>  'Oracle Scheduler Job Notification - %job_owner%.%job_name%.%job_subname% %event_type%',
    body                =>  'Job: %job_owner%.%job_name%.%job_subname%
                            Event: %event_type%
                            Date: %event_timestamp%
                            Log id: %log_id%
                            Job class: %job_class_name%
                            Run count: %run_count%
                            Failure count: %failure_count%
                            Retry count: %retry_count%
                            Error code: %error_code%
                            Error message: %error_message%',
    events              =>  'JOB_ALL_EVENTS',
    filter_condition    =>  NULL);

Checked table DBA_SCHEDULER_JOB_RUN_DETAILS, job run as per schedule.

Checked table DBA_SCHEDULER_NOTIFICATIONS, email notification associated with above job.

Job is running, but I don't get email notification.

I have checked SMTP server and credentials using third party application and email triggered. So SMTP and credentials are correct.

Something goes wrong in it. I searched internet and referred Oracle doc, but no idea what cause the issue.

Is there way to check email log or cause..?

Advice me to sort out this issue. Thanks in advance.