Formula URL Button Error Code 2 for all users but me

I am trying to add a button to a form to change the value of a text field on the same record to a specific value when the button is clicked.  It works perfectly for me, and when I initially implemented it, I thought I had tested it for all other users, successfully.

However, several other users, all of whom are authorized users in the app, and all of whom have read, write, and delete access to the table in question have come back to me saying that when they attempt to use the button, they get the following error:

<qdbapi>
<link type="text/css" id="dark-mode" rel="stylesheet" href=""/>
<style type="text/css" id="dark-mode-custom-style"/>
<action>API_EditRecord</action>
<errcode>2</errcode>
<errtext>Invalid input</errtext>
<errdetail>
[User] can edit data but you're testing as that user, so your change wasn't saved
</errdetail>


<rid>21</rid>
<num_fields_changed>0</num_fields_changed>
<update_id/>

</qdbapi>

Now, when I click the button, it works, but when I test as any other user, it does not.

This is my button code:

URLRoot() & "db/" & Dbid() &
"?act=API_EditRecord&apptoken=hb83yebjxiy9yb9csgmqgstsss&_fid_44=Approved&rid="
&[Record ID#]
& "&rdr=" & URLEncode(URLRoot() & "db/" & Dbid() & "?act=dr&rid=" & [Record ID#])


I have tried it with and without apptokens enabled, and have attempted to get it to work with user tokens instead of app tokens, but have not seen any change in results.  

I'm losing my mind just a little bit here.  If the users can access the app, can access and edit the table, why does this button only work for me?

How can I get it to work for all users?

Thanks!

Jason