do you get an error in your console about headers?
if your api is written in php add this to the .htaccess to see if it helps. Best way to see if its a CORS issue, just run in from a device, if that works you have a cors issue.
Header add Access-Control-Allow-Origin "*"
Header add Access-Control-Allow-Methods "GET,POST,OPTIONS,DELETE,PUT"
Header add Access-Control-Allow-Headers "Content-Type"
Header add Access-Control-Allow-Headers "Authorization"