Admin screen fails after upgrade to 6.2

[rudders18]

After upgrading to version 6.2 I cannot access the admin area, the client area seems to work fine. After a substantial delay the error message that comes up is:

 

Fatal error: Uncaught exception 'Illuminate\Database\QueryException' with message 'SQLSTATE[HY000]: General error: 2006 MySQL server has gone away (SQL: select * from `tblconfiguration` where `setting` = AllowSmartyPhpTags limit 1) (SQL: select * from `tblconfiguration` where `setting` = AllowSmartyPhpTags limit 1)' in /home/wantatsg/public_html/whmcs/includes/classes/WHMCS/Terminus.php:0 Stack trace: #0 /home/wantatsg/public_html/whmcs/includes/classes/WHMCS/Terminus.php(0): WHMCS\Terminus::whmcsExceptionHandler() #1 [internal function]: WHMCS\Terminus->whmcsExceptionHandler(Object(Illuminate\Database\QueryException)) #2 {main} thrown in /home/wantatsg/public_html/whmcs/includes/classes/WHMCS/Terminus.php on line 0

 

Any ideas anyone?

Thanks