Add element problem

When I add new element, immediately whole site become white i and not seeing previously added elements
I tried add section,div, heading and always the previous elements become white,whole screen is white
Whats the problems here?

Please include your site’s Read-Only Share Link with your question.
A read-only link allows the community to view your project without making any edits to it and help diagnose your issue or provide feedback.

If your project has custom code or layout issues on the published site, please share that URL/URI as well.

Without anything to look at there is no way to answer your question.