title: Quickblox: iOS sdk return error on sending even when message is sent
body: <p>I am using iOS SDK 2.2.4</p>
  
  <p>I am sending message using the method</p>
  
  <pre><code>- (BOOL)sendMessage:(QBChatMessage *)message sentBlock:(void (^)(NSError *error))sentBlock;
  </code></pre>
  
  <p>Sometimes, the sent block returns an error (NSCocoaErrorDomain, 50X), but the message is received by recipient. 
  Once this starts happening, it happens for all messages continuously.</p>
  
  <p>Logging in again fixes the problem.</p>
  
  <p>This is a problem for me because I am showing the error/sent status to user.</p>
  
  <p>Can anyone suggest a workaround/fix for this issue?</p>