Error on register mandatory os parameter provided

Hi, I configured the lite plugin, and ios/android apps, I tested apps notificacions without issues, but when I use the wp-plugin to register the device I get the error:

{
“error”: “500”,
“reason”: “Internal Server Error”,
“detail”: “Mandatory parameter os missing”
}

The strange thing is that I am indicating the parameter correctly according to the documentation:

/pnfw/register?os=iOS&token=f21b048a3ef9d2e6d1b68d0d10c9df36354cdaa559207f870350d542daefd695

I appreciated any help.