Seafile 6.3.14 opening documents with Collabora Online doesn't work

I have Seafile Pro deployed under subdomain.domain
And Collabora online on another machine deployed under othersubdomain.domain
I have the following error from the seahub.log while trying to open docs from seafile:
[ERROR] seahub.wopi.utils:108 get_wopi_dict mismatched tag: line 16, column 2

Here is my

# -*- coding: utf-8 -*-
SECRET_KEY = "*secretkey*"
FILE_SERVER_ROOT = 'http://*subdomain*.*domain*/seafhttp'

    'default': {
        'ENGINE': 'django.db.backends.mysql',
        'NAME': 'seahub_db',
        'USER': '*myuser*',
        'PASSWORD': '*mypassword*',
        'HOST': '',
        'PORT': '3306'

    'default': {
#        'BACKEND': 'django_pylibmc.memcached.PyLibMCCache',
        'BACKEND': 'django.core.cache.backends.memcached.MemcachedCache',
        'LOCATION': '',
    'locmem': {
        'BACKEND': 'django.core.cache.backends.locmem.LocMemCache',

# Attempt limit before showing a captcha when login.

# From 6.1.0 CE version on, Seafile support viewing/editing **doc**, **ppt**, **xls** files via LibreOffice
# Add this setting to view/edit **doc**, **ppt**, **xls** files
OFFICE_SERVER_TYPE = 'CollaboraOffice'

# Enable LibreOffice Online

# Url of LibreOffice Online's discovery page
# The discovery page tells Seafile how to interact with LibreOffice Online when view file online
# You should change `` to your actual LibreOffice Online server address
OFFICE_WEB_APP_BASE_URL = 'https://*othersubdomain*.*domain*'

# Expiration of WOPI access token
# WOPI access token is a string used by Seafile to determine the file's
# identity and permissions when use LibreOffice Online view it online
# And for security reason, this token should expire after a set time period
WOPI_ACCESS_TOKEN_EXPIRATION = 30 * 60   # seconds

# List of file formats that you want to view through LibreOffice Online
# You can change this value according to your preferences
# And of course you should make sure your LibreOffice Online supports to preview
# the files with the specified extensions
OFFICE_WEB_APP_FILE_EXTENSION = ('odp', 'ods', 'odt', 'xls', 'xlsb', 'xlsm', 'xlsx','ppsx', 'ppt', 'pptm', 'pptx', 'doc', 'docm', 'docx')

# Enable edit files through LibreOffice Online

# types of files should be editable through LibreOffice Online
OFFICE_WEB_APP_EDIT_FILE_EXTENSION = ('odp', 'ods', 'odt', 'xls', 'xlsb', 'xlsm', 'xlsx','ppsx', 'ppt', 'pptm', 'pptx', 'doc', 'docm', 'docx')

Anyone have an idea how to get rid of this error?

P.S. Values with italic font and these inside are substituted for privacy reasons.

SystemExit: 1
2019-06-02 12:03:25,328 [INFO] seafes:162 load_seafevents_conf [seafes] use highlighter fvh
2019-06-02 12:04:26,062 [INFO] seafes:162 load_seafevents_conf [seafes] use highlighter fvh
2019-06-02 12:21:30,060 [ERROR] root:1169 prepare_converted_html failed to add_office_convert_task:
Traceback (most recent call last):
File “/path-to-seafile-pro-server/seahub/seahub/utils/”, line 1167, in prepare_converted_html
add_office_convert_task(obj_id, doctype, raw_path)
File “/path-to-seafile-pro-server/seahub/seahub/utils/”, line 1076, in real_func
return func(*args)
File “/path-to-seafile-pro-server/seahub/seahub/utils/”, line 1135, in add_office_convert_task
d = rpc.add_task(file_id, doctype, raw_path)
File “/path-to-seafile-pro-server/seafile/lib64/python2.7/site-packages/pysearpc/”, line 125, in newfunc
ret_str = self.call_remote_func_sync(fcall_str)
File “/path-to-seafile-pro-server/seafile/lib64/python2.7/site-packages/ccnet/”, line 92, in call_remote_func_sync
req_id = self._start_service(client)
File “/path-to-seafile-pro-server/seafile/lib64/python2.7/site-packages/ccnet/”, line 34, in _start_service
rsp = client.read_response()
File “/path-to-seafile-pro-server/seafile/lib64/python2.7/site-packages/ccnet/”, line 29, in read_response
packet = read_packet(self._connfd)
File “/path-to-seafile-pro-server/seafile/lib64/python2.7/site-packages/ccnet/”, line 108, in read_packet
hdr = recvall(fd, CCNET_HEADER_LENGTH)
File “/path-to-seafile-pro-server/seafile/lib64/python2.7/site-packages/ccnet/”, line 11, in recvall
new = fd.recv(remain)
File “/path-to-seafile-pro-server/seahub/thirdpart/gunicorn-19.8.1-py2.7.egg/gunicorn/workers/”, line 196, in handle_abort
SystemExit: 1
2019-06-02 12:21:34,645 [INFO] seafes:162 load_seafevents_conf [seafes] use highlighter fvh