Update: Found root cause. In my case, the background push notification opens the closed app in .background mode, sometimes keychain in the didFinishLaunchingWithOptions method returns nill instead of my tokens.
VictorVl
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Update: Found root cause. In my case, the background push notification opens the closed app in .background mode, sometimes keychain in the didFinishLaunchingWithOptions method returns nill instead of my tokens.