What potential error could be causing the output issue in the PHP code?

The potential error causing the output issue in the PHP code could be due to the incorrect use of the concatenation operator (.) in the echo statement. The concatenation operator should be used to combine strings in PHP, but if not used properly, it can lead to unexpected output. To solve this issue, ensure that the concatenation operator is used correctly to concatenate strings in the echo statement.

// Incorrect concatenation operator causing output issue
$name = "John";
echo "Hello" + $name; // Incorrect use of concatenation operator

// Correct concatenation operator
$name = "John";
echo "Hello " . $name; // Correct use of concatenation operator