The amount of bitcoin doesn't present in my account balance because electrum only searches for balance for the first 20 addresses(index 0-19).
I tried to change the gap_limit to 50000 to make electrum searching for more, but electrum got frozen for hours and unresponsive.
More accurately, Electrum monitors activity of all used wallet addresses starting from index 0 and "gap limit amount" of unused wallet addresses.
If you raise the gap_limit to such a high value, Electrum basically freezes because it has to ask the connected Electrum server for the address history of gap_limit many addresses of your wallet. Likely the connected Electrum server will become unresponsive because it thinks it's a DoS attack with so many address history requests. Not a good idea...