layout update can’t save

Hi, I’m facing a weird problem with my Saved Layouts. When I try to change some layout settings, like changing Items Per Page from “6” to “9”, or changing item layout-Tiles from 4 columns per row to 3 columns per row, after I finish these changes and click the Update button, the preview works correctly and the system message shows “Post Updated”. But when I refresh this page, all my changes are gone and all the settings back to the state before I do my changes. Can anyone help me solve this problem? Thank you.