Recommended PHP Configuration Limits
Many issues that you may run into such as; white screen, demo content fails when importing, empty page and other similar issues are all related to low PHP configuration limits / hosting limits.
The solution is to increase the PHP limits.
You can do this on your own .
1) Find the php.ini file in your Server config files. Hosting CPanel has an option that allows you to edit php.ini, it should looks like on a screenshot
2) Go to the line “max_execution_time=30” .
3) Change it to 360 or any other large value.
4) Change another values from the list below or contact your web host and ask them to increase those limits to a minimum as follows:
max_execution_time 360 memory_limit 128M post_max_size 32M upload_max_filesize 32M max_input_vars 5000