WordPress website section background image not being displayed it turns grey?

Hello All

I have an issue with WordPress, where I set a background image to a section, which appears to work fine but then after a short period turns grey / image is not displayed.

If I log into the admin console and edit the page with Elementor pro, the image is showing as it should be but when viewing the webpage the background is grey / image not displayed.

The website is https://samsul.lk

Anyone else experienced this? Any suggestions would be appreciated

Thanks