Not able to launch Articulate Storyline 360 project in a custom LMS

Hi, I have custom LMS written in .NET/C#. I am trying to launch a storyline 360 project using iframe on one of it's page. The project has been published for LMS/SCORM1.2 I have written the javascript ECMAscript class object and have implemented all the 8 functions of the class API on the same page. But when I try to launch the project, it gets stuck on the first slide with the error message 

An error has occurred:

Error - unable to acquire LMS API, content may not play properly and results may not be recorded. Please contact technical support.

Press 'OK' to view debug information to send to technical support.

and in debug messages I get following messages

200:Thu Jul 28 2022 16:31:32 GMT+0530 (India Standard Time) - In IsLoaded, returning -false
201:Thu Jul 28 2022 16:31:33 GMT+0530 (India Standard Time) - In IsLoaded, returning -false
202:Thu Jul 28 2022 16:31:33 GMT+0530 (India Standard Time) - In IsLoaded, returning -false
203:Thu Jul 28 2022 16:31:33 GMT+0530 (India Standard Time) - In CommitData
204:Thu Jul 28 2022 16:31:33 GMT+0530 (India Standard Time) - In ClearErrorInfo
205:Thu Jul 28 2022 16:31:33 GMT+0530 (India Standard Time) - In IsLoaded, returning -false
206:Thu Jul 28 2022 16:31:33 GMT+0530 (India Standard Time) - In SetErrorInfo - Num=7 Desc=Cannot make calls to the LMS before calling Start
207:Thu Jul 28 2022 16:31:34 GMT+0530 (India Standard Time) - In IsLoaded, returning -false
208:Thu Jul 28 2022 16:31:34 GMT+0530 (India Standard Time) - In IsLoaded, returning -false

 

Please advise

 

Thanks!