During demo install, if you get any errors follow the below steps to install demo content properly.
Step 1. Install a fresh WordPress again and theme
Step 2. Make sure below configuration match your server
– PHP Version: 7.2 or, higher
– upload_max_filesize = 265M
– post_max_size = 265M
– max_input_time = -1
– max_input_vars = 8000
– max_execution_time = 500
– Memory Limit = 512M
To ensure you have the same configuration follow the below process
Go to Dashboard>Tools>Site Health>Info
Under info go to the server and check the configuration
Step 3. Make sure you have SSL installed on your server. If not enable it by installing the plugin called Easy SSL
Step 4. Make sure your uploads folder from wp-content>uploads has the file permission of 775
If you follow the above steps hopefully your issues will be solved.