Hi @debuggingallday
The reason for the error is your append to string variable.
The variable contains multiple email addresses, and get user profile does not allow multiple email addresses to be entered at once.
You can use the split function to split the string variable into an array separated by semicolons, and then add an apply to each to iterate over the array.
Enter the expression item() in get uesr profile.
I have made a test for your reference:


Best Regards,
Levi