Plugin is not working – shortcode name conflict
If another plugin is using the [qrcode] shortcode name you have to either disable that plugin or change the shortcode 5sec QR Codes uses.
Changing the shortcode name is simple. Open 5sec-qrcodes.php with a text editor and find the define statement on line 12. Change “qrcode” into something similar, ie: qrcode2. Close the file and re-upload it on the server.
Can I place multiple QR Codes on the same page/post/screen?
Yes, as many as you like!
Do parameters/variables have to be entered in any particular order?
No, you can define them in any order you like.
QR image is not showing up
Use the debug=1 parameter to see if you made a typing error.
Also, Google Chart API could be down. This happens rarely and lasts only for a couple of minutes. Be patient for a minute or two.
Do I need any additional/special PHP image generating modules?
No, absolutely not! If WP works on your server so will QR Codes.