Reconnection with lastSessionId not resuming the subscriptions

I have developed MeteorDDP in Swift for iOS & macOS. After having a great security layer in mobile OS, each time I switch my app or minimize, it disconnects the socket hence, no longer meteor connectivity established with the server. To overcome, I created a reconnection attempt with the old session-id as mentioned in the below link.

I am still facing a problem that my meteor instance is not resuming old subscribed collections and I need to resub all the previous subscriptions which overload my application.

Any great suggestions to make a better reconnection with previously subscribed collections.