SmartReach starts sending emails from your campaigns within 5 mins. However while scheduling emails from your campaign, SmartReach checks a number of conditions to ensure your prospects are receiving the emails at the right time, and your campaign / email-account quota are not being violated.
Please check if one of the following conditions is causing the confusion:
Your prospects have a different time zone than the "Fallback Time zone" in your Campaign Settings. SmartReach will send the emails in each prospect's time zone if you have provided that while adding the prospects.
The campaign has already sent more than the "Max Emails to be sent per day from this campaign" setting in your Campaign Settings.
The email account has already sent more than the "Maximum number of emails that can be sent per day" setting in "Settings -> Email Accounts -> select email address -> Edit Email Setting"
The prospects have already been sent more emails than hit the daily / weekly sending limits per prospect settings under "Settings -> Sending Limits Per Prospect"
Also, check the delivery window schedule (From and Till times) under your Campaign Settings to ensure that is correctly set.
If you are sending emails via a SMTP email account, then there may be network errors for your SMTP service from time-to-time. In such a case (when we get an error while sending email from your service provider), SmartReach.io will wait for 15-20 minutes and retry sending that email.
If you are still not able to figure out the issue, let us know and we will help you out :)