Cross origin ionic problem

Personal'm kinda new with Ionic 3, and I'm experiencing this error http://localhost:3456/usuario/save. No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://localhost:8100' is therefore not allowed access. The response had HTTP status code 404. %

in my rest %%'m using cors and was thus it

const corsMiddleware = require('restify-cors-middleware')
const cors = corsMiddleware({
preflightMaxAge: 5,
origins: ['*'],
allowHeaders: ['*'],
exposeHeaders: ['*']
})

And my call in the application stayed like this

this.http.post('http://localhost:3456/usuario/save',{user: credentials})
.map(res => res.json()).subscribe(result => {

})

I do not know what else to do.