Will not save settings

Using v1.20

Admin > Watermark:
Watermark settings
Settings not saved!

Same error regardless of choice: off – text – image or any other selections

After clicking “Save Changes” button there is an update msg. stating “Settings Saved” but they are not.

Deactivated all other plugins but still would not work. No errors reported, on page or in error logs.

https://ww.wp.xz.cn/plugins/wp-watermark-site/