firstly my seafdav.conf looks like:
[WEBDAV]
enabled = true
port = 8080
fastcgi = false
share_name = /seafdav
in CE 6.3.2 ubuntu@ARM I see when seafdav is running:
seafile 10212 10207 0 Jul12 ? 00:03:39 /usr/bin/python2.7 -m wsgidav.server.run_server --log-file /media/sda/seafile/logs/seafdav.log --pid /media/sda/seafile/pids/seafdav.pid --port 8080 --host 0.0.0.0
@mydoom could you please list ls -l the content of these directories:
/home/seafile/seafile-server-latest/seahub/thirdpart
/home/seafile/seafile-server-latest/seahub/thirdpart/wsgidav
/home/seafile/seafile-server-latest/seahub/thirdpart/wsgidav/server
check that run_server exists, because it is called by the python path.
BTW, there is no necessity for external WsgiDAV 2.3.0, the system calls the same python module which is pleaced on /thirdpart, at least in seafile CE rpi-version, which works out of the box, without pip install wsgidav. See here my “pip list”:
Package Version
-------------------- ----------------------
acme 0.24.0
appdirs 1.4.3
asn1crypto 0.24.0
attrs 18.1.0
Automat 0.6.0
beautifulsoup4 4.6.0
certifi 2018.4.16
chardet 3.0.4
ConfigArgParse 0.13.0
configobj 5.0.6
configparser 3.5.0
constantly 15.1.0
cryptography 1.9
decorator 4.3.0
dnspython 1.15.0
docopt 0.6.2
enum34 1.1.2
funcsigs 1.0.2
future 0.16.0
html5lib 1.0.1
hyperlink 18.0.0
idna 2.6
imageio 2.3.0
incremental 17.5.0
ipaddress 1.0.22
josepy 1.1.0
Landscape-Client 16.3+bzr834
lxml 3.5.0
mercurial 3.7.3
mock 2.0.0
moviepy 0.2.3.5
mysqlclient 1.3.7
ndg-httpsclient 0.5.0
ngxtop 0.0.2
numpy 1.14.3
olefile 0.45.1
packaging 17.1
PAM 0.4.2
parsedatetime 2.4
pbr 4.0.3
Pillow 5.1.0
pip 10.0.1
pip-review 1.0
pipdate 0.2.4
psutil 5.0.1
pyasn1 0.4.3
pyasn1-modules 0.0.7
pycparser 2.18
pycrypto 2.6.1
PyICU 1.9.2
pyOpenSSL 17.3.0
pyparsing 2.2.0
pyRFC3339 1.0
pyserial 3.0.1
Pyste 0.9.10
python-apt 1.1.0b1+ubuntu0.16.4.2
python-debian 0.1.32
python-memcached 1.59
python2-pythondialog 3.3.0
pytz 2018.4
requests 2.18.4
requests-toolbelt 0.8.0
service-identity 17.0.0
setuptools 39.2.0
simplejson 3.8.1
six 1.11.0
tabulate 0.8.2
tqdm 4.23.4
Twisted 18.4.0
urllib3 1.22
webencodings 0.5.1
wheel 0.29.0
zope.component 4.4.1
zope.event 4.3.0
zope.hookable 4.2.0
zope.interface 4.5.0
Check /home/seafile/seafile-server-latest/seahub/thirdpart/wsgidav/server # cat run_server.py for more infos about seafdav/wsgidav
and have fun 
Edited: Added picture
and working with Bitkinex Client as well.
so it would seem the issue can occur when having CherryPy installed, atleast in my situation. Not sure why I had it installed.