Why is demo content not being imported?
When it comes to importing demo content, before you hit import, disable all 3rd party plugins (to free up server resources), then go to import, open chrome developer tools, hit Import, and watch console for errors. When some error occur refresh import page and repeat the process. Importing demo content must reach 100% without displaying error in the console. So repeat it until console is clear (sometimes you have to repeat process for 3-4 times or maybe more).
Please understand that this is common issue when importing demo with all theme authors since demos become more robust so they can satisfy needs of all customers, so issue is usually triggered by lower server resources. Usually it is due to low WordPress memory limit https://codex.wordpress.org/Editing_wp-config.php#Increasing_memory_allocated_to_PHP and also due to low PHP directives, so it would be good if you can increase these values or ask your hosting service to do that for you:
max_execution_time = 300;
memory_limit = 128M;
upload_max_filesize = 64M;
post_max_size = 256M;
Also check instructions regarding import in theme documentation http://demo.select-themes.com/stockholm-help/#!/getting_started_importing_demo_content
If you continue to have problems with import, you can always submit a ticket to our support and they will try to import demo content for you. Just provide WordPress admin access in your ticket:
Website login URL