PlaySMS suport for sending SMS over HTTPS to Kannel with HTTPs (SSL)

Dear dev,

I am having difficulties to send sms through Kannel configured with SSL (HTTPS).
2018-09-08 12:41:51 [2150] [1] ERROR: SSL read failed: OpenSSL error 1: error:00000001:lib(0):func(0):reason(1).

While I have enabled https on playSMS through config.php, I think some of the methods do not take care of the https option but use only http. This is specific to kannel Plugin.

I would like make the necessary changes to be able to support both http and https BUT I can not find exactly where PlaySMS Core sends SMS (to Kannel). from the main send sms form, whcih function is responsible to send an SMS (to Kannel Plugin and then to the recipeint phone from kannel)

Kindly let me know.

here is the code that send SMS via Kannel: