What is the potential issue with the syntax used in the PHP code provided in the forum thread?

The potential issue with the syntax used in the PHP code provided in the forum thread is the incorrect use of the concatenation operator. In PHP, the concatenation operator is a period (.) and not a plus sign (+). To fix this issue, you need to replace the plus sign with a period to correctly concatenate strings in PHP.

// Incorrect code
$first_name = "John";
$last_name = "Doe";
$full_name = $first_name + " " + $last_name;

// Corrected code
$first_name = "John";
$last_name = "Doe";
$full_name = $first_name . " " . $last_name;