PayPal payment gateways may generate specific subscription log entries. Troubleshoot and resolve Referenced transaction or order is too old errors while using a PayPal payment gateway module. After attempting to migrate to the new PayPal Payments payment gateway module from a previous PayPal® module, you are experiencing problems with subscriptions. Troubleshoot and resolve L_SHORTMESSAGE0 => Security error errors while using a PayPal payment gateway module. Troubleshoot and resolve PayPal connection errors. Troubleshoot and resolve Transaction ID already exists errors for PayPal Payments transactions. Troubleshoot and resolve issues that cause Invalid Receiver emails while using a PayPal payment gateway module. Troubleshoot and resolve Not Supported errors while using a PayPal payment gateway module. Troubleshoot and resolve Things don't appear to be working at the moment errors while using a PayPal payment gateway module. Troubleshoot and resolve Unrecognized Currency errors while using a PayPal payment gateway module. Troubleshoot and resolve Error Code PE101, Account is not approved to sell., or Account has been closed. errors while using the 2CheckOut payment gateway module. Troubleshoot and resolve Plesk permission denied errors. Troubleshoot and resolve PHP Fatal error: Maximum execution time of 300 seconds exceeded in /path/to/file.php errors in WHMCS. Troubleshoot and resolve 503 Service Temporarily Unavailable, Page not Found, Timeout, or 502 Bad Gateway errors. Troubleshoot and resolve Plesk permission denied errors. Troubleshoot and resolve a POP3 cron not running emails and WHMCS Pop Cron Did Not Run errors. Troubleshoot and resolve General error: 3988 Conversion from collation utf8mb3_unicode_ci into latin1_swedish_ci impossible for parameter errors. Troubleshoot and resolve Error: read failed - connection closed? errors. Troubleshoot and resolve issues with pricing displaying incorrectly in the shopping cart. Troubleshoot and resolve Product attribute Package Name XXX Not Found on Server errors.