Usually after store transfer to another hosting, Magento administrator can't login to Magento admin panel.

To fix this issue, you need to enter correct cookie domain and cookie path in your Magento store database. Connect to your Magento database using MySQL command line or phpMyAdmin and open 'core_config_data' MySQL table.

Find these entries and replace them with new cookie domain and path:

[cc lang='abap' line_numbers='false']
web/secure/base
web/unsecure/base
web/cookie/cookie_domain
web/cookie/cookie_path

Clear Magento cache directory (/var/cache), and try to login to Magento admin panel.