How to upload file to 3rd party api (in this case is CloudSign api)

[legacy_user]

Dear Everyone,

I'm sorry, but since I haven't found an answer to my question yet, I created one from here.

My problem

I cannot upload a file to the CloudSign API using JavaScript in a Kintone App.

CloudSign API that I am using:

• cloudsign-web_api | 0.10.4 | CloudSign | SwaggerHub | /documents/{documentID}/files

Attempts

This is a list of solutions that I tried and failed:

• Using the Kintone JavaScript Proxy API: failed, error "invalid upload."
  • Proxy Request - Kintone Developer Program
• Using the Kintone JavaScript Proxy Upload API: It did not actually fail, but I don't understand how to use it. My error was "invalid upload."
  • Proxy File Upload - Kintone Developer Program
• Using fetch: CORS error.

I would really appreciate it if somebody with experience in this could help me.

[legacy_user]

Dear Tiến Đạt Trần

Unfortunately, we are unsure what is happening with the information provided.

By looking at the error, the request's content of the target API may be incorrect, but we do not know the details of the CloudSign API or the content of the request being executed.

Please let us know the details of the request you made and the error details.

Regards,

Yasu