What potential issues can arise with the Same-Origin Policy when using AJAX in PHP?

The Same-Origin Policy can pose issues when making AJAX requests in PHP if the request is being made to a different domain or subdomain. To solve this, you can set the appropriate headers in your PHP script to allow cross-origin requests. This can be done by sending the 'Access-Control-Allow-Origin' header with the value of '*' to allow requests from any origin.

header("Access-Control-Allow-Origin: *");