wiki-v1 Clicking Save Changes results in 'Error: undefined' popup

Actual behavior

Clicking Save Changes results in 'Error: undefined' popup and hang for between 30 seconds and a minute.
Next, the wiki will be down completely for a few minutes. Firefox will show the standard error: we cannot find this page.
After a couple of minutes (approx. 10 minutes), the login screen will appear [we are back online] and I have to login again. Time is approx. 12.40.
I have four pages on my Wiki. But the [restarted?] wiki will now only show two pages: Home and Hosting.
12:58: In ‘All Pages’ view, the wiki will still only show pages Home and Hosting. I can however access my page ‘Study’ directly via http://[my IP address]:2086/study.
13:21: In ‘All Pages’ view, the wiki will now show 3 pages: Home, Hosting and Study. The fourth and last page still does not show up in ‘All pages’ view.
13:25: I restart nginx and wiki.js.

Expected behavior

Save page when I click save changes.

Steps to reproduce the behavior

I do not know how to reproduce this. But it does happen often (every day).

Firefox developer console output

Usage of window.controllers/Controllers is not supported anylonger. Do not use this for UA detection. vendor.js line 1 > Function:3:17840 The connection with ws://[my VPS IP adress]:2086/socket.io/?EIO=3&transport=websocket&sid=__i8W58O-j4TVoMhAABI was interrupted during page load. vendor.js:1:472056

How I run wiki.js

I run wiki.js behind nginx on a VPS, on Ubuntu 18.04. I access wiki.js from [my VPS IP address]:2086. Port 2086 is open in ufw.
I use a bitbucket free private repository and use the master branch. I use login with username and password instead of private key.
wikijs v1.0.102
git v2.11.0
nginx v1.10.3
Nodejs v10.13.0

Probably it has something to do with the nginx and virtualhost config settings

I followed tutorials to get the wiki working, but I do not know the ratio behind every command I copied into my config files.

Virtual host settings in nginx config (the one in /sites-available, which is symlinked to /sites-enable):

server { root /var/www/html; listen 80; listen [::]:80; server_name wikijs; location / { proxy_pass http://localhost:2086; try_files $uri $uri/ =404; } add_header Strict-Transport-Security "max-age=15768000; includeSubdomains; preload"; add_header X-Frame-Options SAMEORIGIN; add_header X-Content-Type-Options nosniff; }

Main nginx config file settings -> /etc/nginx/nginx.conf:

user www-data; worker_processes auto; pid /run/nginx.pid; include /etc/nginx/modules-enabled/*.conf;

events { worker_connections 768; # multi_accept on; }

http { sendfile on; tcp_nopush on; tcp_nodelay on; keepalive_timeout 65; types_hash_max_size 2048;

    include /etc/nginx/mime.types;
    default_type application/octet-stream;

    access_log /var/log/nginx/access.log;
    error_log /var/log/nginx/error.log;

    gzip on;
    gzip_disable "msie6";

    include /etc/nginx/sites-enabled/*;

}

Nginx error log -> nano /var/log/nginx/error.log

Empty

Nginx access log -> nano /var/log/nginx/access.log

12:55: ran command pm2 show wiki

Approx 13.00: Logs wiki –-lines output -> pm2 logs wiki --lines 100 [part of it]

[TAILING] Tailing last 100 lines for [wiki] process (change the value with --lin es option) /srv/wikijs/logs/wiki-error-0.log last 100 lines:

0|wiki | (node:12108) [DEP0079] DeprecationWarning: Custom inspection function on Objects via .inspect() is deprecated 0|wiki | (node:14352) [DEP0079] DeprecationWarning: Custom inspection function on Objects via .inspect() is deprecated

13.20: Logs wiki –-lines output (no change wrt when I ran the command at 13.00):

Nov 18 '18 12:11 powerusewiki

How much RAM do you have?

Nov 21 '18 05:11 NGPixel

Excuse me for my late reaction, I am currently working/studying a lot.

This cloud VPS from OVH has 2GB RAM.

Nov 27 '18 21:11 powerusewiki