How do I link php slim with Ionic

this is the code in ionic to link to my slim api:

postData(credentials, type){

return new Promise((resolve, reject) =>{
  let headers = new Headers();"http://slimapp:8080/api/signup", JSON.stringify(credentials), {headers: headers}).
  subscribe(res =>{
  }, (err) =>{


credentials is my data and type is"signup"

and this is the slim php code tp match the route
$app->post(’/api/signup’, function(Request $request, Response $response){
// my function is here

when i connect postman with php slim, everything works well, but when i connect it with ionic, this error comes up:
[404]: /api/signup - No such file or directory

how to fix this?

The most likely reason is you are not hitting the correct route with your postman request. Are you certain the URL is correct? Are you sending it as a POST request? If you look at the server log, does it show it as a POST request at the correct URL?