File "/usr/lib/python3/dist-packages/electrum/gui/qt/main_window.py", line 1416, in spend_max
    tx = make_tx(None)
  File "/usr/lib/python3/dist-packages/electrum/gui/qt/main_window.py", line 1413, in <lambda>
    is_sweep=False)
  File "/usr/lib/python3/dist-packages/electrum/wallet.py", line 1211, in make_unsigned_transaction
    tx.locktime = get_locktime_for_new_transaction(self.network)
  File "/usr/lib/python3/dist-packages/electrum/wallet.py", line 199, in get_locktime_for_new_transaction
    if chain.is_tip_stale():
  File "/usr/lib/python3/dist-packages/electrum/blockchain.py", line 490, in is_tip_stale
    header = self.header_at_tip()
  File "/usr/lib/python3/dist-packages/electrum/blockchain.py", line 486, in header_at_tip
    return self.read_header(height)
  File "/usr/lib/python3/dist-packages/electrum/blockchain.py", line 201, in func_wrapper
    return func(self, *args, **kwargs)
  File "/usr/lib/python3/dist-packages/electrum/blockchain.py", line 478, in read_header
    raise Exception('Expected to read a full header. This was only {} bytes'.format(len(h)))