PHP - setcookie(); not working

There are several reasons why the setcookie() function may not be working. Some possible issues include:

• The setcookie() function must be called before any output is sent to the browser. Make sure that the function is called before any HTML or whitespace is outputted.
• The path and domain parameters in the setcookie() function may be set incorrectly. Make sure that the path and domain match the settings on your server.
• The browser may have cookies disabled. Ask the user to check their browser settings to ensure cookies are enabled.
• The server may be configured to not accept cookies. Check your server's configuration to ensure that cookies are allowed.

It is always helpful to check the return value of the setcookie function. If the function returns false, you can check the last error by calling error_get_last() function.

It would be helpful if you could share the code which you are trying to use setcookie function and any error message you are getting.