Meanwhile another site with vps but other theme is still running normally
Hi,
You could ask your hosting provider to check that for you, there might be logs containing information about the issue and possible cause. They could provide more assistance in the matter.
I switched to another host but did not change the situation.So the error here is not due to hosting.
Then something else is the cause. So you say that your post pages provide 404 errors. Try some general solutions in this case
– http://www.wpbeginner.com/wp-tutorials/how-to-fix-wordpress-posts-returning-404-error/
– https://www.greengeeks.com/tutorials/article/how-to-fix-a-404-error-in-wordpress-posts/
– https://premium.wpmudev.org/blog/fix-wordpress-404-errors-when-post-page-exists/
– https://blondish.net/how-to-fix-wordpress-posts-returning-404-error/
