Collectives™ on Stack Overflow

Find centralized, trusted content and collaborate around the technologies you use most.

Teams

Q&A for work

Connect and share knowledge within a single location that is structured and easy to search.

I am trying to load image from URL on the iphone, image is there and I can open it in safari with same link, but not in the app:

Error Domain=NSURLErrorDomain Code=-1003 "A server with the specified hostname 
could not be found." UserInfo={NSUnderlyingError=0x17024f810 
{Error Domain=kCFErrorDomainCFNetwork Code=-1003 "(null)" 
UserInfo={_kCFStreamErrorCodeKey=50331647, _kCFStreamErrorDomainKey=6147928288}},
 NSErrorFailingURLStringKey=https://........, NSErrorFailingURLKey=https://.........
Code of request:
func downloadImage(userEmail: String, onCompletion: @escaping (UIImage) -> Void) {
    print("Download Started")
    let route = "\(baseURL as String)\(userEmail as String)\(baseURLparameters as String)"
    let url = URL(string: route)
    getDataFromUrl(url: url!) { (data, response, error)  in
        guard let data = data, error == nil else {
            print("===failed:", error ?? "dunno")
            print("===url:", url?.absoluteString ?? "dunno")
            return
        print(response?.suggestedFilename ?? url!.lastPathComponent )
        print("Download Finished")
        DispatchQueue.main.async() { () -> Void in
            onCompletion(UIImage(data: data)!)
                I'm assuming Swift 3 on iOS 10... have you tried temporarily replacing getDataFromUrl(...) with UIApplication.shared.open(url, options: [:], completionHandler: nil) just to see if it properly launches Safari and connects to the URL /(retrieves the image) correctly?
– DonMag
                Mar 24, 2017 at 12:38
                This can also be misleadingly reported because of an URL doing a redirect (e.g. HTTP 30X with a Location header) and the URL to be redirected to being the one "not foundable". In that case, iOS reports the initial original URL, not the one having the issue. In React Native with WebView, the onShouldStartLoadWithRequest method can be used to debug this.
– salzo
                Apr 24 at 5:28
                Unfortunately the error is very misleading here. It isn't that DNS isn't working, it's that the app might not have permission to access the network at all! Simply selecting "Outgoing Connections (Client)" will allow you to make network requests.
– spfursich
                May 4, 2018 at 17:27
                I have lost two days on this, it didn't make any sense at all! Thanks, you saved me hours of headaches.
– Michele Dall'Agata
                Jul 19, 2018 at 9:46
                this works but if you go to Capabilities you might not see App Sandbox there. I had to follow this answer on where to find it and to get it to appear. After you follow the steps it will take 5 - 10 minutes before it appears: stackoverflow.com/a/58833674/4833705
– Lance Samaria
                May 17, 2020 at 13:47
                i cannot see this in Xcode 12.4, can anyone please suggest with the steps?  Thanks in advance
– Arshad Shaik
                Aug 20, 2021 at 4:33
                @Arshad Shaik select Blue Project Icon on the left > signing & capabilities > scroll down to App sandbox (if missing: plus icon to add capability)
– de.
                Aug 20, 2021 at 6:21
                @de. it didn't work, need to add "App Sandbox" in ".entitlements" file and set to "YES" and will see it in capabilities
– Arshad Shaik
                Aug 20, 2021 at 9:15
This happened in my case because one of the paths in our development servers was internal to our firewall/intranet/VPN and my device was not on our internal wi-fi.
Frustrating and confusing because it was working in the simulator and not on a device.
This error would suggest as DNS related issue.There is some problem with DNS server reached through our WiFi network. So we change DNS server and fix this problem. 
Remove cache and try again.
If there is a url you can GET (instead POST) on the same server.
And Also, turning off wifi and using 3G makes the error go away.
                you might be right, maybe it's about the corporate VPN not being configured properly on this device, because on other device it just works
– Async-
                Mar 24, 2017 at 11:34
The host name in your URL is wrong because the message you are getting back explicitly states it can't find a server with that host name.
The mst likely cause is that you have forgotten to put a forward slash between the base URL and the email e.g. if your base URL is 
http://example.com
and your email is 
jeremyp@example.com
You construct
http://example.comjeremyp@example.com
Put a break point on the line that creates the URL and inspect the string it is trying to create it from. It'll probably then be pretty obvious exactly what you are doing wrong. 
                man, it's not, the full URL is correctly made, and I can see it opens in the safari browser. It's not about the URL, URL is correct
– Async-
                Mar 24, 2017 at 10:30
                I am seeing the URL as constructed by the program at runtime, and also output to the log as well as part of the error, sorry I can't put URL here, but it's properly constructed
– Async-
                Mar 24, 2017 at 11:32
                in my case the base URL is not just a website address, it's a proper URL of the API ending with "/"   so adding email to it is correct, and the URL it outputs at the runtime is correct, it looks like the app can't access it
– Async-
                Mar 24, 2017 at 11:38
                @JeremyP: Can you please let me know if there are different error codes for DNS resolution failure/ timeout and for invalid host names. I am facing similar issue, I want to understand if it's a host name error (or) if its a DNS issue
– Vivek Maran
                Sep 11, 2017 at 16:11
        
Thanks for contributing an answer to Stack Overflow!
Please be sure to answer the question. Provide details and share your research!
But avoid …
Asking for help, clarification, or responding to other answers.
Making statements based on opinion; back them up with references or personal experience.
To learn more, see our tips on writing great answers.