Problem when importing user groups from a csv file

[mmuhammadeuss]

I'm using sniperphish 2.1. my csv file has several users registered normally. when I do an import, I receive these error messages:

**Fatal error: Uncaught Error: Call to undefined function isValidEmail() in C:\xampp\htdocs\spear\manager\userlist_campaignlist_mailtemplate_manager.php:236
Stack trace:
#0 C:\xampp\htdocs\spear\manager\userlist_campaignlist_mailtemplate_manager.php(34): uploadUserCVS(Object(mysqli), Array)
#1 {main}
thrown in C:\xampp\htdocs\spear\manager\userlist_campaignlist_mailtemplate_manager.php on line 236

DataTables warning: table id=table_user_list - Invalid JSON response. For more information about this error, please see http://datatables.net/tn/1

Fatal error: Uncaught TypeError: sizeof(): Argument #1 ($value) must be of type Countable|array, null given in C:\xampp\htdocs\spear\manager\userlist_campaignlist_mailtemplate_manager.php:295
Stack trace:
#0 C:\xampp\htdocs\spear\manager\userlist_campaignlist_mailtemplate_manager.php(36): getUserGroupFromGroupIdTable(Object(mysqli), Array)
#1 {main}
thrown in C:\xampp\htdocs\spear\manager\userlist_campaignlist_mailtemplate_manager.phpon line295
**