Generates a numeric OTP and sends it to the specified mobile number via SMS,
using the Reseller-tier OTP service. The OTP is injected into the message
template using the %m escape character.

Authentication: Query-parameter based — username + password.

How %m works:

URL-encoding note: % must be encoded as %25 in a query string,
so %m becomes %25m. Example: msg=Your%20one%20time%20OTP%20is%20%25m

Example Request (from your listed URL):

GET https://api.rmlconnect.net/OtpApi/generatesms
  ?username=xxx-xxx
  &password=xxxx
  &msisdn=xxxx
  &msg=Your%20one%20time%20OTP%20is%20%25m
  &source=xxxxx
  &tagname=ENSURESERV
  &otplen=5
  &exptime=60

Success Response Format (plain text):

1701|<destination>|<message_id>

Tier-Aware Credit Errors:

• 1025 → End User credit exhausted
• 1026 → Reseller credit exhausted
• 1027 → Distributor credit exhausted