Scheduled Refresh Not Working for Web source on Window Authentication

Thanks for your reply.

Sql Agent Service was stopped, therefore scheduled refresh plan was not creating. 

Now, Scheduled Plan has created but getting new error:

"An error has occurred.
Data source error: Login failed for data source ‘http://ApiServer.com/api/user/getusers’.

Hide error details
SessionID: ddssf0fb-3423-XXXX-XXX-XXX5d6771XX
[0] -1055784932: The credentials provided for the Web source are invalid. (Source at http://ApiServer.com/api/user/getusers.). The exception was raised by the IDbCommand interface."

Below are requests detail that is coming on API SERVER:

From PowerBI Desktop:
2020-07-21 08:52:29 [API SERVER IP] GET /api/user/getusers - 80 Domain\UserName [User IP] Microsoft.Data.Mashup+(https://go.microsoft.com/fwlink/?LinkID=304225) - 200 0 0 46

From Scheduled Refresh[BI report Server]:
2020-07-21 09:14:43 [API SERVER IP] GET /api/user/getusers - 80  [Missing domain\user]  - [API SERVER IP] Microsoft.Data.Mashup+(https://go.microsoft.com/fwlink/?LinkID=304225) - 401 1 3221225581 0

As can be seen above, Domain\User is missing in request that is coming from BI report server while scheduled refreshing. 

Is there any alternative to Scheduled refresh in  said scenario?