First of all, open the Chrome developer console in the inpect to determine the cause of the error. If a parameter called undefined is added to the end of the url in the console logs, delete the s_website_form value in the class in the error section. The problem will be solved.

Hi,

There is something wrong with the form that you have created, issue might be in the template itself or in the controller which is executed on clicking the submit button.

Have a look at the following and see whether it helps.

1. Record Data To Backend Models From Website Form - Without Code
   

2. How To Create Website Form And Record Data Into Backend Model In Odoo
   

Thanks

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