Notice (8): Trying to get property 'photoURL' of non-object [APP/Controller/UsersController.php, line 124]
Notice (8): Trying to get property 'firstName' of non-object [APP/Controller/UsersController.php, line 125]
Notice (8): Trying to get property 'lastName' of non-object [APP/Controller/UsersController.php, line 126]
Notice (8): Trying to get property 'displayName' of non-object [APP/Controller/UsersController.php, line 127]
Notice (8): Trying to get property 'email' of non-object [APP/Controller/UsersController.php, line 128]
Notice (8): Trying to get property 'email' of non-object [APP/Controller/UsersController.php, line 129]
Warning (512): Unable to emit headers. Headers sent in file=/var/www/html/home/vendor/cakephp/cakephp/src/Error/Debugger.php line=954 [CORE/src/Http/ResponseEmitter.php, line 71]
Warning (2): Cannot modify header information - headers already sent by (output started at /var/www/html/home/vendor/cakephp/cakephp/src/Error/Debugger.php:954) [CORE/src/Http/ResponseEmitter.php, line 168]
Warning (2): Cannot modify header information - headers already sent by (output started at /var/www/html/home/vendor/cakephp/cakephp/src/Error/Debugger.php:954) [CORE/src/Http/ResponseEmitter.php, line 197]
Error: Expression is missing operator (IS, IS NOT) with `null` value.

Expression is missing operator (IS, IS NOT) with null value. 📋

InvalidArgumentException
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            $operator '!=';
        }
        if ($value === null && $this->_conjunction !== ',') {
            throw new InvalidArgumentException('Expression is missing operator (IS, IS NOT) with `null` value.');
        }
        return new ComparisonExpression($expression$value$type$operator);
    }

If you want to customize this error message, create templates/Error/error500.php