Xamarin iOS- NFC Reader- INFCNdefReaderSessionDelegate- DidDetect not getting called - xamarin.ios

Question

I have a Cross-Platform Xamarin app iOS and wanted to add the nfc-scan functionality.
I followed the link- https://learn.microsoft.com/en-us/xamarin/ios/platform/introduction-to-ios11/corenfc
These have been configured properly-
Info.plist privacy key.
Entitlements.plist entry.
provisioning profile with NFC Tag Reading capability.
I've put all into a new RFIDReader class which is present in a iOS Class Library, and this method gets called from my ViewModel class.
If I run this code, everything looks fine. The scan starts when I press the button on my phone, it shows the blue tick symbol but then it never gets into one of the implemented methods DidDetect, DidInvalidate.
Do you know what the reason could be?
Here's my code-
/// <summary>
/// Class for RFID form control
/// </summary>
public sealed class RFIDReader : UIViewController, IRFIDReader, INFCNdefReaderSessionDelegate
{
/// <summary>
/// The scanning session
/// </summary>
private NFCNdefReaderSession session;
/// <summary>
/// The task completion source
/// </summary>
private TaskCompletionSource<string> tcs;
/// <summary>
/// Gets the handle
/// </summary>
/// <value>The handle</value>
public new IntPtr Handle { get; }
/// <summary>
/// Read the string characters from scanning
/// </summary>
/// <returns>Task status</returns>
public Task<string> ScanCode()
{
if (!NFCNdefReaderSession.ReadingAvailable)
{
//// NFC is not available or disabled
throw new Exception(FormsErrorConstants.NearFieldCommunicationDisabled);
}
this.tcs = new TaskCompletionSource<string>();
this.session = new NFCNdefReaderSession(this, DispatchQueue.CurrentQueue, true);
this.session.BeginSession();
return this.tcs.Task;
}
/// <summary>
/// Called when a tag is successfully read
/// </summary>
/// <param name="session">Session</param>
/// <param name="messages">Messages</param>
public void DidDetect(NFCNdefReaderSession session, NFCNdefMessage[] messages)
{
var bytes = messages[0].Records[0].Payload.Skip(3).ToArray();
var message = Encoding.UTF8.GetString(bytes);
this.tcs.SetResult(message);
}
/// <summary>
/// Called when an error occurs or the 60 second timeout is reached
/// </summary>
/// <param name="session">Session</param>
/// <param name="error">Error</param>
public void DidInvalidate(NFCNdefReaderSession session, NSError error)
{
var readerError = (NFCReaderError)(long)error.Code;
if (readerError != NFCReaderError.ReaderSessionInvalidationErrorFirstNDEFTagRead &&
readerError != NFCReaderError.ReaderSessionInvalidationErrorUserCanceled)
{
// some error handling
}
this.tcs.SetResult(string.Empty);
}
/// <summary>
/// Clean up method
/// </summary>
public new void Dispose()
{
this.Dispose(true);
GC.SuppressFinalize(this);
}
/// <summary>
/// Clean up method
/// </summary>
/// <param name="isDisposing">is disposing</param>
private new void Dispose(bool isDisposing)
{
if (isDisposing)
{
// Dispose
this.session.InvalidateSession();
this.session = null;
}
}
}