Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/electrum/gui/qt/send_tab.py", line 573, in do_pay_or_get_invoice
    self.do_pay_invoice(self.pending_invoice)
  File "/usr/lib/python3/dist-packages/electrum/gui/qt/send_tab.py", line 585, in do_pay_invoice
    self.pay_onchain_dialog(self.window.get_coins(), invoice.outputs)
  File "/usr/lib/python3/dist-packages/electrum/gui/qt/send_tab.py", line 237, in pay_onchain_dialog
    conf_dlg = ConfirmTxDialog(window=self.window, make_tx=make_tx, output_value=output_value, is_sweep=is_sweep)
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3/dist-packages/electrum/gui/qt/confirm_tx_dialog.py", line 186, in __init__
    BlockingWaitingDialog(window, _("Preparing transaction..."), self.update_tx)
  File "/usr/lib/python3/dist-packages/electrum/gui/qt/util.py", line 364, in __init__
    task()
  File "/usr/lib/python3/dist-packages/electrum/gui/qt/confirm_tx_dialog.py", line 89, in update_tx
    self.tx = self.make_tx(fee_estimator)
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3/dist-packages/electrum/gui/qt/send_tab.py", line 227, in <lambda>
    make_tx = lambda fee_est: self.wallet.make_unsigned_transaction(
                              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3/dist-packages/electrum/wallet.py", line 1670, in make_unsigned_transaction
    tx.locktime = get_locktime_for_new_transaction(self.network)
                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3/dist-packages/electrum/wallet.py", line 218, in get_locktime_for_new_transaction
    if chain.is_tip_stale():
       ^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3/dist-packages/electrum/blockchain.py", line 486, in is_tip_stale
    header = self.header_at_tip()
             ^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3/dist-packages/electrum/blockchain.py", line 482, in header_at_tip
    return self.read_header(height)
           ^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3/dist-packages/electrum/util.py", line 1273, in func_wrapper
    return func(self, *args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3/dist-packages/electrum/blockchain.py", line 469, in read_header
    self.assert_headers_file_available(name)
  File "/usr/lib/python3/dist-packages/electrum/blockchain.py", line 431, in assert_headers_file_available
    raise FileNotFoundError('Electrum headers_dir does not exist. Was it deleted while running?')
FileNotFoundError: Electrum headers_dir does not exist. Was it deleted while running?