Really insane situation here, OctoberCMS Build 419 my plugin settings does not save properly anymore on my live website but still does save properly on my local dev machine. What could be the cause of this ?

I already checked this:

• exactly the same code
• the backend user permissions are correct
• others plugins settings works fine
• when I delete the record for my plugin settings in the database, the settings page is still showing up the same values as previously.

due to file cache permission issue. resolved now