Cukoo web interface not working

[vivekhimalayas]

My issue is:

Web interface doesn't work when starting cukoo.

My Cuckoo version and operating system are:

OS - Ubuntu 18.0.4
Cukoo - 2.0.7

This can be reproduced by:

The log, error, files etc can be found at:

2021-04-12 09:03:26,432 [cuckoo] DEBUG: Increasing resource limit for number of open files to 1048576
Checking for updates...
Oops! Cuckoo failed in an unhandled exception!
Sometimes bugs are already fixed in the development release, it is therefore recommended to retry with the latest development release available https://github.com/cuckoosandbox/cuckoo
If the error persists please open a new issue at https://github.com/cuckoosandbox/cuckoo/issues

=== Exception details ===
Cuckoo version: 2.0.7
OS version: posix
OS release: Ubuntu 18.04 bionic
Python version: 2.7.17
Python implementation: CPython
Machine arch: x86_64
Modules: alembic:1.0.10 androguard:3.0.1 argparse:1.2.1 asn1crypto:0.24.0 attrs:20.3.0 beautifulsoup4:4.5.3 capstone:3.0.5rc2 chardet:2.3.0 cheetah:2.4.4 click:6.6 colorama:0.3.7 configparser:4.0.2 contextlib2:0.6.0.post1 cryptography:2.1.4 cuckoo:2.0.7 django-extensions:1.6.7 django:1.8.4 dpkt:1.8.7 ecdsa:0.16.1 egghatch:0.2.3 elasticsearch:5.3.0 enum34:1.1.6 flask-sqlalchemy:2.4.0 flask:0.12.2 functools32:3.2.3.post2 future:0.18.2 gevent:1.2.2 greenlet:1.0.0 httpreplay:0.2.6 idna:2.6 importlib-metadata:2.1.1 ipaddress:1.0.23 itsdangerous:1.1.0 jinja2:2.9.6 jsbeautifier:1.6.2 jsonschema:3.2.0 keyring:10.6.0 keyrings.alt:3.0 libvirt-python:4.0.0 m2crypto:0.37.1 mako:1.1.4 markupsafe:1.1.1 meld3:1.0.2 olefile:0.43 oletools:0.51 pathlib2:2.3.5 peepdf:0.4.2 pefile2:1.2.11 pillow:3.2.0 pip:20.3.4 pycrypto:2.6.1 pyelftools:0.24 pygobject:3.26.1 pyguacamole:0.6 pymisp:2.4.106 pymongo:3.0.3 pyopenssl:20.0.1 pyrsistent:0.16.1 python-dateutil:2.4.2 python-editor:1.0.4 python-magic:0.4.12 python:2.7.17 pythonaes:1.0 pyxdg:0.25 requests:2.13.0 roach:0.1.2 scandir:1.10.0 scapy:2.3.2 secretstorage:2.3.1 setuptools:44.1.1 sflock:0.3.10 six:1.11.0 sqlalchemy:1.3.3 supervisor:3.3.1 tlslite-ng:0.6.0 typing:3.7.4.3 unicorn:1.0.1 urllib3:1.26.4 virtualenv:15.1.0 wakeonlan:0.2.2 werkzeug:1.0.1 wheel:0.30.0 wsgiref:0.1.2 yara-python:3.6.3 zipp:1.2.0

2021-04-12 09:03:27,787 [cuckoo] ERROR: AttributeError: exit
Traceback (most recent call last):
File "/usr/local/lib/python2.7/dist-packages/cuckoo/main.py", line 297, in main
cuckoo_init(level, ctx)
File "/usr/local/lib/python2.7/dist-packages/cuckoo/main.py", line 170, in cuckoo_init
check_version(ctx.ignore_vuln)
File "/usr/local/lib/python2.7/dist-packages/cuckoo/core/startup.py", line 113, in check_version
params={"version": version}, timeout=6
File "/usr/local/lib/python2.7/dist-packages/requests/api.py", line 70, in get
return request('get', url, params=params, **kwargs)
File "/usr/local/lib/python2.7/dist-packages/requests/api.py", line 56, in request
return session.request(method=method, url=url, **kwargs)
File "/usr/local/lib/python2.7/dist-packages/requests/sessions.py", line 488, in request
resp = self.send(prep, **send_kwargs)
File "/usr/local/lib/python2.7/dist-packages/requests/sessions.py", line 609, in send
r = adapter.send(request, **kwargs)
File "/usr/local/lib/python2.7/dist-packages/requests/adapters.py", line 423, in send
timeout=timeout
File "/usr/local/lib/python2.7/dist-packages/requests/packages/urllib3/connectionpool.py", line 600, in urlopen
chunked=chunked)
File "/usr/local/lib/python2.7/dist-packages/requests/packages/urllib3/connectionpool.py", line 356, in _make_request
conn.request(method, url, **httplib_request_kw)
File "/usr/lib/python2.7/httplib.py", line 1099, in request
self._send_request(method, url, body, headers)
File "/usr/lib/python2.7/httplib.py", line 1139, in _send_request
self.endheaders(body)
File "/usr/lib/python2.7/httplib.py", line 1095, in endheaders
self._send_output(message_body)
File "/usr/lib/python2.7/httplib.py", line 898, in _send_output
self.send(msg)
File "/usr/lib/python2.7/httplib.py", line 874, in send
self.sock.sendall(data)
File "/usr/local/lib/python2.7/dist-packages/requests/packages/urllib3/contrib/pyopenssl.py", line 311, in sendall
sent = self._send_until_done(data[total_sent:total_sent + SSL_WRITE_BLOCKSIZE])
File "/usr/local/lib/python2.7/dist-packages/requests/packages/urllib3/contrib/pyopenssl.py", line 301, in _send_until_done
return self.connection.send(data)
File "/usr/local/lib/python2.7/dist-packages/OpenSSL/SSL.py", line 1644, in send
with _from_buffer(buf) as data:
AttributeError: exit