FCM push notification via AlamoFire – URLSessionTask failed with error: Could not connect to the server – Ios swift

I’m trying to implement FCM to send a push notification (using the legacy api), but am unable to do so.

I have verified that my server key (taken from Firebase console) and device token are accurate, and I have successfully sent a push note to my device via Postman.

However, I am unable to do so via code. I am calling the below code from my simulator and "attempting" to send a push note to my physical device.

let urlString: String = "https://fcm/googleapis.com/fcm/send"
let key = "key=[my server key]"

let headers: HTTPHeaders = [
    "Content-Type": "application/json",
    "Authorization": key
]

let notificationParameters: Parameters = [
    "to": "[my push token of physical device]",
    "notification": [
        "title": "My title",
        "body": "My body"
    ]
]

print("1")
AF.request(urlString, method: .post, parameters: 
notificationParameters, encoding: JSONEncoding.default, headers: 
headers).responseJSON { response in
    print("3")
    switch response.result {
    case .success:
        printSuccess("Successfully sent notification")
    case .failure(let error):
        print("Failed to send notification: (error)")
        print(error.errorDescription)
        print(error.failureReason)
    }
    print("4")
}
print("2")

Here’s the log:

1
2
2022-03-31 15:23:24.725607-0500 Wurtle with Friends[22207:12775410] 
[connection] nw_socket_handle_socket_event [C3.1:3] Socket SO_ERROR 
[61: Connection refused]
2022-03-31 15:23:24.727572-0500 Wurtle with Friends[22207:12775410] 
Connection 3: received failure notification
2022-03-31 15:23:24.727789-0500 Wurtle with Friends[22207:12775410] 
Connection 3: failed to connect 1:61, reason -1
2022-03-31 15:23:24.728130-0500 Wurtle with Friends[22207:12775410] 
Connection 3: encountered error(1:61)
2022-03-31 15:23:24.729779-0500 Wurtle with Friends[22207:12775409] 
[boringssl] boringssl_metrics_log_metric_block_invoke(153) Failed 
to log metrics
2022-03-31 15:23:24.731134-0500 Wurtle with Friends[22207:12775410] 
Task <B52206D8-E22D-4D8F-B3F5-815692558860>.<1> HTTP load failed, 
0/0 bytes (error code: -1004 [1:61])
2022-03-31 15:23:24.736922-0500 Wurtle with Friends[22207:12775410] 
Task <B52206D8-E22D-4D8F-B3F5-815692558860>.<1> finished with error 
[-1004] Error Domain=NSURLErrorDomain Code=-1004 "Could not connect 
to the server." UserInfo={_kCFStreamErrorCodeKey=61, 
NSUnderlyingError=0x60000279c300 {Error 
Domain=kCFErrorDomainCFNetwork Code=-1004 "(null)" UserInfo=
{_NSURLErrorNWPathKey=satisfied (Path is satisfied), interface: 
en1, _kCFStreamErrorCodeKey=61, _kCFStreamErrorDomainKey=1}}, 
_NSURLErrorFailingURLSessionTaskErrorKey=LocalDataTask <B52206D8-
E22D-4D8F-B3F5-815692558860>.<1>, 
_NSURLErrorRelatedURLSessionTaskErrorKey=(
    "LocalDataTask <B52206D8-E22D-4D8F-B3F5-815692558860>.<1>"
), NSLocalizedDescription=Could not connect to the server., 
NSErrorFailingURLStringKey=https://fcm/googleapis.com/fcm/send, 
NSErrorFailingURLKey=https://fcm/googleapis.com/fcm/send, 
_kCFStreamErrorDomainKey=1}
3
Failed to send notification: sessionTaskFailed(error: Error 
Domain=NSURLErrorDomain Code=-1004 "Could not connect to the 
server." UserInfo={_kCFStreamErrorCodeKey=61, 
NSUnderlyingError=0x60000279c300 {Error 
Domain=kCFErrorDomainCFNetwork Code=-1004 "(null)" UserInfo=
{_NSURLErrorNWPathKey=satisfied (Path is satisfied), interface: 
en1, _kCFStreamErrorCodeKey=61, _kCFStreamErrorDomainKey=1}}, 
_NSURLErrorFailingURLSessionTaskErrorKey=LocalDataTask <B52206D8-
E22D-4D8F-B3F5-815692558860>.<1>, 
_NSURLErrorRelatedURLSessionTaskErrorKey=(
    "LocalDataTask <B52206D8-E22D-4D8F-B3F5-815692558860>.<1>"
), NSLocalizedDescription=Could not connect to the server., 
NSErrorFailingURLStringKey=https://fcm/googleapis.com/fcm/send, 
NSErrorFailingURLKey=https://fcm/googleapis.com/fcm/send, 
_kCFStreamErrorDomainKey=1})
Optional("URLSessionTask failed with error: Could not connect to 
the server.")
4

This is my first time implementing FCM and I’ve been stuck on it for a while now, so any help is appreciated. Thank you