A white screen of death happens when there is a PHP error on the site but WP_Debug isn’t enabled on the server.

Please follow these instructions:

Step 1. Make sure your host comply with minimum requirements: Theme requirements.
Step 2. If step 1 did not help you then delete unnecessary plugins from folder wp-content/plugins via hosting or FTP and then try again.
Step 3. Finally if none of above steps worked then enable WP_Debug so you can read what the actual error is and thus fix the problem.