Unable to add custom webhook to opensearch alert

[prakash]

Versions (relevant - OpenSearch/Dashboard/Server OS/Browser):

opensearch dashboard: 2.12.0
OS: Windows 11
Browser: Chrome

Describe the issue:
i have a asp.net web api project running with a webhook api
it’s purpose is to get message and write in a text file.
it’s a simple code, attached in screenshot. when i run the project, i can send data via postman and it get’s written to file.
when i am trying to put it in opensearch channel custom webhook,
it throws error.
have attached all screenshot below.
i change webhook url value to application/json still same issue
is there some setting in opensearch i am missing?

Configuration:
running opensearch dashboard via docker on Windows .

Relevant Logs or Screenshots:

[prakash]

[prakash]

[pablo]

@prakash I assume that you also run OpenSearch in a docker. If that’s the case, localhost regards the container’s localhost instead of the docker host. Try using FQDN or the IP address of your docker host.