How to resolve the error "Cannot set property videoFrameRate" when changing frameRate using Script?

Hi,

I used to change all of the sequence's frame rate in premiere pro using this following script lines by extendscript toolkit.

var currentSettings = app.project.sequences[0].getSettings();
currentSettings.videoFrameRate = (1/60);
app.project.sequences[0].setSettings(currentSettings);

I just simplified the code out of for loop. By this code first sequence item in project file should change it's framerate to 60 fps. But it throws me an error says "Cannot set property videoFrameRate" it was working some days ago. The error is happening on second line. It didn't assigning value to the frameRate of collected settings. I didn't updated the premiere. But now it's not working. What should I do to make it work again?

Premiere Version : 14.3.0

Thank you.