Dynamics 365 allows us to customize Entity forms by adding custom controls to the fields for a more enhanced User Experience. For example, we can add ‘Flip – Switch’ as a control for a ‘Two Option Set’ field. This ‘Flip – Switch’ control changes the look and feel of a ‘Two Option Set’ field.
I added this control for the OOTB ‘Do not Allow Emails’ field on a custom Contact form and ends up looking something like this on the form.
But if the same form is being used by one of the Portal’s Entity Forms, you will start getting the following error on the page. This makes the Portal webpage using this Entity Form unusable. Just a note that the error below is also very common, so it’s sometimes very difficult to determine what the exact error is. In this case we know it’s because of the custom control we had added.
Also, even if the ‘Flip-Switch’ control is not being used on a field (has not been selected for Web, Phone or Tablet), adding it alone on the form will break Portal Form. So, to remedy this error you would need to select the X shown in the screenshot below.
So, while setting up the forms which will be used in the Dynamics 365 Portal, this is one of the things that you need to be careful of.
The version of Dynamics 365 I tested this on is Version 1710 (184.108.40.20619).