httpClient requests with withCredentials don't persist PHP sessions

I log a user in with this: + ‘/login’, this.credentials, { withCredentials: true })

and then I send a request like this:

this.http.get(this.endpointProvider.apiEndpoint + ‘/check-session’, { withCredentials: true })

and there is no PHP session, but only when I deploy it via xcode to my device.

I’m using version 3.9.9 of the framework and xCode 11.3