Continous error in browser console after login in ERPNext

Install / Update Setup
1

Getting continuous error in the console as following for one of the two instances on the same server while another instance works smoothly:

http://x.x.x.x:xxxx/socket.io/?EIO=3&transport=polling&t=NQJT3Kg

The output of sudo supervisorctl status is as follows:

erpnext-redis:erpnext-redis-cache                 RUNNING   pid 1982, uptime 7 days, 2:07:53
erpnext-redis:erpnext-redis-queue                 RUNNING   pid 1981, uptime 7 days, 2:07:53
erpnext-redis:erpnext-redis-socketio              RUNNING   pid 1983, uptime 7 days, 2:07:53
erpnext-web:erpnext-frappe-web                    RUNNING   pid 1989, uptime 7 days, 2:07:53
erpnext-web:erpnext-node-socketio                 RUNNING   pid 1986, uptime 7 days, 2:07:53
erpnext-workers:erpnext-frappe-default-worker-0   RUNNING   pid 1976, uptime 7 days, 2:07:53
erpnext-workers:erpnext-frappe-long-worker-0      RUNNING   pid 1978, uptime 7 days, 2:07:53
erpnext-workers:erpnext-frappe-schedule           RUNNING   pid 1977, uptime 7 days, 2:07:53
erpnext-workers:erpnext-frappe-short-worker-0     RUNNING   pid 1979, uptime 7 days, 2:07:53

The output of the sudo netstat -tlnp is as following:

Active Internet connections (only servers)

Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name
tcp 0 0 0.0.0.0:8036 0.0.0.0:* LISTEN 1879/nginx: master
tcp 0 0 127.0.0.1:13000 0.0.0.0:* LISTEN 1982/redis-server 1
tcp 0 0 0.0.0.0:9036 0.0.0.0:* LISTEN 1879/nginx: master
tcp 0 0 0.0.0.0:80 0.0.0.0:* LISTEN 1879/nginx: master
tcp 0 0 0.0.0.0:82 0.0.0.0:* LISTEN 1879/nginx: master
tcp 0 0 127.0.0.53:53 0.0.0.0:* LISTEN 1151/systemd-resolv
tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 1765/sshd
tcp 0 0 127.0.0.1:11000 0.0.0.0:* LISTEN 1981/redis-server 1
tcp 0 0 0.0.0.0:5432 0.0.0.0:* LISTEN 1854/postgres
tcp 0 0 127.0.0.1:8000 0.0.0.0:* LISTEN 1989/python3
tcp 0 0 127.0.0.1:12000 0.0.0.0:* LISTEN 1983/redis-server 1
tcp6 0 0 :::9000 :::* LISTEN 1986/node
tcp6 0 0 :::3306 :::* LISTEN 1672/mysqld
tcp6 0 0 :::22 :::* LISTEN 1765/sshd
tcp6 0 0 :::5432 :::* LISTEN 1854/postgres

This is continous error getting generated after login into one of the ERPNext instance on the server. The strange thing is there is no error for another instance on the same error.

I have referred so many post related to this issue but none worked for me. I am using :
ERPNext: v13.0.0-beta.4 (version-13-beta)
Frappe Framework: v13.0.0-beta.5 (version-13-beta)
and ubuntu 18.04 server

Major Problems:

  1. When clicking on Save", “Submit” or any action button then it takes 2-3 and sometimes 5 minutes to perform the action successfully.
  2. Unable to import data using the Import screen. It shows continuously the “Importing” message.

Any help would be a help to resolve the critical issue.