pgadmin4 python bug?

Hello

I start pgadmin4 with the following command:

python /usr/local/lib/python2.7/site-packages/pgadmin4/pgAdmin4.py

I open the browser
On the website (port 5050), when I open a db connection, I get the the
message:
Object type <type 'unicode'> cannot be passed to C code

This is the terminal-output:
Starting pgAdmin 4. Please navigate to http://127.0.0.1:5050 in your
browser.
2018-04-26 23:28:13,503: ERROR  pgadmin:        Object type <type
'unicode'> cannot be passed to C code
Traceback (most recent call last):
  File
"/usr/local/lib/python2.7/site-packages/pgadmin4/pgadmin/browser/server_groups/servers/__init__.py",
line 962, in connect
    if password is not None else server.password
  File
"/usr/local/lib/python2.7/site-packages/pgadmin4/pgadmin/utils/crypto.py",
line 31, in encrypt
    cipher = AES.new(pad(key), AES.MODE_CFB, iv)
  File "/usr/local/lib/python2.7/site-packages/Crypto/Cipher/AES.py",
line 200, in new
    return _create_cipher(sys.modules[__name__], key, mode, *args, **kwargs)
  File
"/usr/local/lib/python2.7/site-packages/Crypto/Cipher/__init__.py", line
55, in _create_cipher
    return modes[mode](factory, **kwargs)
  File
"/usr/local/lib/python2.7/site-packages/Crypto/Cipher/_mode_cfb.py",
line 230, in _create_cfb_cipher
    cipher_state = factory._create_base_cipher(kwargs)
  File "/usr/local/lib/python2.7/site-packages/Crypto/Cipher/AES.py",
line 100, in _create_base_cipher
    result = start_operation(c_uint8_ptr(key),
  File "/usr/local/lib/python2.7/site-packages/Crypto/Util/_raw_api.py",
line 109, in c_uint8_ptr
    raise TypeError("Object type %s cannot be passed to C code" %
type(data))
TypeError: Object type <type 'unicode'> cannot be passed to C code

What should I do?

uname -a
FreeBSD ftc2 11.1-RELEASE-p1 FreeBSD 11.1-RELEASE-p1

Should I write this problem on a FreeBSD mailinglist?
Franz