so everything back to wordpress not betheme
its better ask your quastion here or hosting
sry
https://wordpress.org/support/forums/
So I found the issue. For anyone that will face the problem in the future. I discovered it was the template - 'decor'. I tried another template and it was perfect.
So I went to increase the memory limit from 256M to 512M. Then tried to edit the Decor template again and then it worked.
Hope this will be useful to someone else in the future.