Valid If in User Settings

[jonbowles84]

I am trying to set up a login with a public app making use of the "User Settings" table.
I have a table called "User" where I will enter emails of people who can use the app.

As long as the email they enter into the UserSettings[Email] exists in the User[Email] they will have access. Problem is how to get around the VALIF_IF. 

How do I have the UserSettings[Email] to be an email entry form and not a dropdown when I have a formula in the Valid If section. It just appears as a dropdown with the emails from the User[Email] column.
I dont want to display a selection of emails to choose from, just allow manual entry. I have tried variations of this type of formula, but its always the same result of the dropdown:

IN(USERSETTINGS("Email"),User[Email])

[TeeSee1]

First of all, using the usersettings as a security mechanism has been warned not to be used and not supported by Google many time in the community.

https://help.appsheet.com/en/articles/948946-user-settings-appropriate-use-and-limitations

Since you do not seem to be capturing user password, I do not know if this constitutes a violation of the terms of Service or whatever agreement you have with Google.

Having said that, why do you even need to enter a valid-if expression in the first place?

Whoever has the lawful access should know exactly what to enter in their user setting.

Or if the data is public, then why can't you show the list of emails (should be just a filter value for convenience) anyway?

It is a bad idea anyway and I do not think you get any useful answers here....

[Joseph_Seddik]

Adding to @TeeSee1 comments, it is either a public app with public data, or an app that require sign-in. You cannot have both.

If you need to introduce a level of control in your public app given to some people, then you should make two apps. For example, a read-only public app, and another app with write access given only to invited signed-in app users. 

[Steve]

What you're attempting directly violates the AppSheet license, if I understand it correctly.

Even aside from that, there is NO way to secure your app. A savvy user of the app will easily be able to find the email addresses known to the app.

The reason it's called a "public" app is because ALL of its data is effectively available to the public.