Email alert doesn't always send out a email

[N-W]

I have a alert that should be sent out every 8 am and 4pm everyday even if there is no results. I can only see the email get sent out sometimes even if there is less results then the trigger. I've sent it out to several diffrent email addresses to make sure there is no email filter that stops it.
Splunk version is 8.0.4.1 we are going to upgrade soon however i would need the alert set up before then.

This is my configures:

Title: Error Report

Alert type: Scheduled - Run on Cron Schedule
Time Range: Last 24 Hours
Cron Expression: 00 8,16 * * *
Expires: 60 min
Trigger alert When: Number of Results is less than 999999
Trigger: Once
When Triggered: Email
Include: Inline Table & Attach CSV

When i check in the python.log it says that: sendemail:139 was done for all of the alerts. Does anyone know what there can be that is stopping it from working?

[somesoni2]

What's the search you're using?

Also, if you're only interested in the count check, you should be including a status command in your search and may be avoid using "Inline Table & Attach CSV". 

[N-W]

The search is something along line this:

index=testIndex_* host=* "Trigger_error_alert_by_Splunk"
| table _time, errorLogMessage, index, sourcetype