I have checked all logs and it seems that the problem is here:
05:42 W/SQLiteConnectionPool: The connection pool for database '+data+data+com_...+files+..._cblite' has been unable to grant a connection to thread 3211 (CBLManagerWorkExecutor) with flags 0x1 for 36.019 seconds.
Similar log is repeated during all downloading phase from the gateway server.
Any suggestion where the problem may be?