Check to see what the start/appear date and time is in "Appear as". You always want to make sure the time you want to send the push notification falls within the pre-set range you set up. This will be in the "Appear at" section of the page. The start time should be set up 12 hours before a push message is sent to ensure that the message will be sent at the time you designate it to go out.
If this does not take care of the issue, please contact us: firstname.lastname@example.org