Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/electrum/gui/qt/send_tab.py", line 263, in spend_max
    tx = make_tx(None)
         ^^^^^^^^^^^^^
  File "/usr/lib/python3/dist-packages/electrum/gui/qt/send_tab.py", line 256, in <lambda>
    make_tx = lambda fee_est, *, confirmed_only=False: self.wallet.make_unsigned_transaction(
                                                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3/dist-packages/electrum/util.py", line 483, in do_profile
    o = func(*args, **kw_args)
        ^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3/dist-packages/electrum/wallet.py", line 1936, in make_unsigned_transaction
    tx.locktime = get_locktime_for_new_transaction(self.network)
                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3/dist-packages/electrum/wallet.py", line 210, in get_locktime_for_new_transaction
    if chain.is_tip_stale():
       ^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3/dist-packages/electrum/blockchain.py", line 491, in is_tip_stale
    header = self.header_at_tip()
             ^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3/dist-packages/electrum/blockchain.py", line 487, in header_at_tip
    return self.read_header(height)
           ^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3/dist-packages/electrum/util.py", line 1190, in func_wrapper
    return func(self, *args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3/dist-packages/electrum/blockchain.py", line 479, in read_header
    raise Exception('Expected to read a full header. This was only {} bytes'.format(len(h)))
Exception: Expected to read a full header. This was only 0 bytes