MessageExtension returned a NSURLErrorDomain when requesting the server

Question

I'm developing iOS message extension to filter the unwanted message. The plugin needs a help from server to filter the message. However, the iOS returned the error NSURLErrorDomain while requesting the server.

Based on the official document, I have done the following steps:

• I added Associated Domains capability with value: messagefilter:mydomain.io
• I defined the key/value pair in Info.plist of Message Extension. ILMessageFilterExtensionNetworkURL has value: https://mydomain.io/api/v1/sms

The code that I test the request as follows:

let url = URL(string: "https://mydomain.io/api/v1/sms")!

var request = URLRequest(url: url)
request.setValue("application/json", forHTTPHeaderField: "Content-Type")
request.setValue("you-value-goes-here", forHTTPHeaderField: "X-API-KEY")


let task = URLSession.shared.dataTask(with: request) { data, _, error in
    if let data = data {
        print(data)
    } else if let error = error {
        print("Http failed: \(error)")
    }
}

task.resume()

From the stack trace, as far as I known, there is a problem with dns resolution. Why does this happened and how to fix this case?

[0] (null)  "_kCFStreamErrorCodeKey" : Int32(-72000)    
[1] (null)  "NSUnderlyingError" : domain: "kCFErrorDomainCFNetwork" - code: 18446744073709550613    
[2] (null)  "_NSURLErrorFailingURLSessionTaskErrorKey" : "LocalDataTask <B496A974-7009-4FCE-BF45-FEC07BA1E8DF>.<1>" 
[3] (null)  "_NSURLErrorRelatedURLSessionTaskErrorKey" : 1 element  
[4] (null)  "NSLocalizedDescription" : "A server with the specified hostname could not be found."   

Thanks