Protecting preloaded variable

I am trying to protect a preloaded variable in our questionnaire. I followed the instructions in the support article, but I keep getting this error.

I took care to name the file as protected__variables.tab. The file contains the following:

variable__name
insurance_old

The insurance_old variable is a multi-select variable.

What could be the reason for the error?

File should be named protected__variables, but from the error message you posted in seems to be called portected__variables

@andrii Thank you for pointing it out! That indeed was the problem.