ConnectAsync hangover

[hosseinGanjyar]

After a while, I can't connect to Telegram and api hangover on await client.ConnectAsync section :

** I dont have any error or timeout!!!

var store = new FileSessionStore();
TelegramClient client = new TelegramClient(apiId, apiHash, store, sessionNumber.ToString());
await client.ConnectAsync();

** I use my sessions on IIS and using above code into WCF api, now I don't understand that why occur this problem? Thanks