assignee cannot open form

{"responseCode" :401, "message" : "You're not authorized to use (\/formuser\/login\/redirect","content" : [], "duration" 5ms , "info" : https: \/\/api.jotform.com\/docs#formuser-login-redirect

This is what appears when my assignee tries to access the form. Can someone explain why and why it's not allowing him to use the form?

Thanks.

Hello, can you please share the form and the assignee email address so that we can check?

May we know if the assignee is trying to open the form in the JotForm Mobile Form app or in the web browser?

May we know if you have tried to remove and add the assignee again?

Help guide:https://www.jotform.com/help/652-Adding-assignees-to-your-form

Looking forward for your response.