Adobe sign Create Web Form API exmaple or workflow

Question

Everyone.

I'm new to Adobe Sign API integration.

I need a good example of Create Web Form and end FormFields API using jQuery Ajax or workflow.

I have done like this.

1. generate an access token.
2. create a web form with the state "DRAFT".
3. change form state as "AUTHORING".
4. put form fields.
5. change form state as "ACTIVE".
6. get web form url.

But got an error when signing a document and clicking confirm. this is error image Please help me with this.