I can't Access system -> Configuration -> Sales -> Payment methods after server migration. its shows server error 500
log details:
2016-02-01T10:38:27+00:00 ERR (3): Notice: Undefined index: httponly in /var/www/vhosts/domain.com/httpdocs/app/code/core/Mage/Core/Model/Session/Abstract/Varien.php on line 96
2016-02-01T10:38:27+00:00 ERR (3): Notice: Undefined index: secure in /var/www/vhosts/domain.com/httpdocs/app/code/core/Mage/Core/Model/Session/Abstract/Varien.php on line 98
2016-02-01T10:38:27+00:00 ERR (3): Notice: Undefined index: domain in /var/www/vhosts/domain.com/httpdocs/app/code/core/Mage/Core/Model/Session/Abstract/Varien.php on line 100
2016-02-01T10:38:29+00:00 ERR (3): Warning: simplexml_load_string(): Entity: line 90: parser error : Start tag expected, '<' not found in /var/www/vhosts/domain.com/httpdocs/lib/Varien/Simplexml/Config.php on line 510
2016-02-01T10:38:33+00:00 ERR (3): Notice: Use of undefined constant MCRYPT_BLOWFISH - assumed 'MCRYPT_BLOWFISH' in /var/www/vhosts/domain.com/httpdocs/lib/Varien/Crypt/Mcrypt.php on line 56
2016-02-01T10:38:33+00:00 ERR (3): Notice: Use of undefined constant MCRYPT_MODE_ECB - assumed 'MCRYPT_MODE_ECB' in /var/www/vhosts/domain.com/httpdocs/lib/Varien/Crypt/Mcrypt.php on line 60
link : index.php/admin/system_config/edit/section/payment/key/
mcrypt
is not installed in your new server. Check with the your hosting and get it installed. This link might help further : magestore.com/magento-installation/… – Prateek Feb 1 '16 at 10:48