We will suggest you to try with SMSAlert.
Make sure you have configured SMS option properly, copied api key properly or not.
If not, check out this video and follow steps: https://www.youtube.com/watch?v=GKvwhwAYmUE
Check 1: login on smsalert website: https://www.smsalert.co.in/Dashboard
and check, whether you have credits or not?
If you dont have any credits, you may need to purchase credits.
While purchasing, select India and *Promotional* messages.
Check 2: (If you are using free credits on smsalert)
make sure, you have selected sender id: DEMO in Book Keeper Windows
Check 3: (If you are using purchased credits on smsalert)
Click on sender id, make sure you have only 1 sender id and that is approved. If it is not approved, contact SMSAlert customer support.
Check 4: Check Template & Sys Templates
Make sure these are blanks, you *should not* create any template. If you have created any template, delete these templates.
Check 5: Customer phone number
Make sure, you have typed customer phone number in phone number field
- Just type 10 digit phone number, don't add +91 or 0 before it
- Number should not be in DND service