Keepkey Domain register AssertionError: None

Hello, I am using the wallet with my KeepKey. The KeepKey is up to date. I set it up normally and transferred a small amount to Namecoin. Next I tried to register a name. What was a little strange is that I was asked for a password (not the password for the KeepKey) because I never set one. I then just clicked "OK". The relevant data was entered and then it appeared that an error had occurred (see below).

Is that up to me? Is that a bug in the program? I hope it's okay that I made a new issue here.

$./electrum-nmc-nc3.3.10-x86_64.AppImage 
qt.qpa.xcb: QXcbConnection: XCB error: 3 (BadWindow), sequence: 1107, resource id: 10488252, major code: 40 (TranslateCoords), minor code: 0
Traceback (most recent call last):
  File "/tmp/user/1000/.mount_electrHJYM6o/usr/lib/python3.6/site-packages/electrum_nmc/electrum/gui/qt/configure_name_dialog.py", line 155, in register_and_broadcast
    name_autoregister(identifier.decode('ascii'), value.decode('ascii'), recipient_address)
  File "/tmp/user/1000/.mount_electrHJYM6o/usr/lib/python3.6/site-packages/electrum_nmc/electrum/gui/qt/main_window.py", line 2107, in <lambda>
    return lambda *args: f(method, args, self.password_dialog)
  File "/tmp/user/1000/.mount_electrHJYM6o/usr/lib/python3.6/site-packages/electrum_nmc/electrum/commands.py", line 149, in _run
    result = f(*args, **{'password':password})
  File "/tmp/user/1000/.mount_electrHJYM6o/usr/lib/python3.6/site-packages/electrum_nmc/electrum/commands.py", line 123, in func_wrapper
    return func(*args, **kwargs)
  File "/tmp/user/1000/.mount_electrHJYM6o/usr/lib/python3.6/site-packages/electrum_nmc/electrum/commands.py", line 745, in name_autoregister
    status = self.addtransaction(new_tx)
  File "/tmp/user/1000/.mount_electrHJYM6o/usr/lib/python3.6/site-packages/electrum_nmc/electrum/commands.py", line 123, in func_wrapper
    return func(*args, **kwargs)
  File "/tmp/user/1000/.mount_electrHJYM6o/usr/lib/python3.6/site-packages/electrum_nmc/electrum/commands.py", line 973, in addtransaction
    if not self.wallet.add_transaction(tx.txid(), tx):
  File "/tmp/user/1000/.mount_electrHJYM6o/usr/lib/python3.6/site-packages/electrum_nmc/electrum/address_synchronizer.py", line 203, in add_transaction
    assert tx_hash, tx_hash
AssertionError: None

namecoin / electrum-nmc

Keepkey Domain register AssertionError: None #296