The error message could have come because of any of the below-provided reasons:
1. If you have exhausted the number of OTP transactions associated with your account. To check your Email/SMS OTP transactions please click here.
2. If you have set up the wrong Email/SMS Messages template.
If you have any further queries, please contact us using the support form in the plugin or email us at firstname.lastname@example.org. We will help you resolve the issue.