I'm not able to send templates, getting error messages. (or) Messages are not being delivered

I'm not able to send templates, getting error messages. (or) Messages are not being delivered

1. Please check if your template's status reads 'approved' . If so, please use the template after 15-20 minutes.
2. If it is a session message that is not being delivered, please check whether you have received a retry option under the exclamatory symbol. Try resending the message after 2-3 minutes.