Frappe V8.0.20 & later: socketio error

This suggests the npm WARN is not an issue -

As for this:
http:6787/socket.io/?EIO=3&transport=polling&t=1493040997461-38 Failed to load resource: net::ERR_NAME_NOT_RESOLVED

Maybe restart services or cycle the server itself -

frappe@erpnext:~/bench-repo$ sudo supervisorctl stop all
frappe@erpnext:~/bench-repo$ sudo supervisorctl start all

These logs may give you an idea of the problem:

frappe@erpnext:~/frappe-bench$ ls -al logs | grep redis
-rw-r–r-- 1 frappe root 0 Nov 24 15:18 redis-cache.error.log
-rw-r–r-- 1 frappe root 52620 Apr 5 18:48 redis-cache.log
-rw-r–r-- 1 frappe root 0 Nov 24 15:18 redis-queue.error.log
-rw-r–r-- 1 frappe root 56447 Apr 5 18:48 redis-queue.log
-rw-r–r-- 1 frappe root 0 Nov 24 15:18 redis-socketio.error.log
-rw-r–r-- 1 frappe root 56447 Apr 5 18:48 redis-socketio.log

frappe@erpnext:~/frappe-bench$ less /var/log/nginx/error.log

Here’s another approach Error when loading site - #3 by slushpuppy