Is id field numeric, if so then your sql query should be like this.
$sql = mysql_query("UPDATE Credentials SET `Email` = '".$email."', `Password` = '".$password."', `Permission` = '".$permission."', `Status` = '".$status."' WHERE `ID` = $id ") // id = $id without quotes because it is numeric
IF this above query is not working try this one
mysql_query("UPDATE Credentials SET `Email` = '{$email}', `Password` = '{password}', `Permission` = '{$permission}', `Status` = '{$status}' WHERE `ID` = $id")
If this too doesn't works paste the query in phpmyadmin or your database try running the query online if possible.Also set error_reporting(E_ALL) to let browser display error;
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