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I have tested your form and I'm unable to sign in the widget; however, it seems like you have not properly integrated DocuSign in your form, I have now cloned one of your forms and integrated it, I was able to successfully sign, here are some screenshots about it:
Here is also the link to my cloned form where you can see the widget is working fine: https://form.jotform.com/62878896286986
I would suggest you to please remove the widget and add it once again to your form, integrate it and test, if the issue still persists, please let us know.