Developer Portal 'Try It' Fails to Upload File for multipart/form-data

Hi, I'm currently using Azure API Management and have created an HTTP API that accepts file uploads via multipart/form-data. The API works correctly when tested using tools like Postman or through my own backend integration, the file is successfully received and processed, so I'm sure the API itself is functioning as expected.

However, when using the Developer Portal's 'Try It' feature, file upload fails. The API receives either an empty file or a request without any file content, even though I do select a file via the upload icon in the portal UI.

From my understanding, this appears to be a limitation or bug in the Developer Portal, it seems to be not able to handle properly the binary file data in multipart/form-data requests.

May I know how to resolve this issue?

Thanks in advance!