Switching on SSL when moving to a new server can cause a serious problem if your certificate is not installed/configured correctly and your website will display an error as a result of that. Because there’s no way of logging back into Admin, you will have to change these settings via PHPMyadmin:
1. Open up admin panel (cPanel or other).
2. Go to phpMyAdmin.
3. Find your Magento Database (you can also look for db name and logins under app/etc/local.xml).
4. Take a backup of your database as explained here.
4. Find table “core_config_data”.
5. Look for the columns “web/secure/use_in_frontend” and “web/secure/use_in_adminhtml”.
6. Edit both values, make them equal to “0”.