Wireless ipad keyboard not recognizing special characters

I am working with a custom web application using Nginx, PHP on a Ubuntu server. When using an iPad mini with a wireless keyboard (purchased at Apple Store), all of the keys work except the "special upper case keys", e.g., @, #, $, etc. When using an attached keyboard to a PC, laptop, or mac mini, everything works. In my /var/www/(program name) index.ini file, this is located under the <header> tag ... meta http-equiv="content-type" content="text/html; charset=UTF-8". I also tried another wireless keyboard not from Apple and it does the same thing. Can I get suggestions as to what else I can check? Thank you. P. S. the special characters do display properly on the screen.