mosquitto: increase connection limits

I am trying to increase my mosquitto connection limits. when my mosquitto broker reaches above 1010 clients connection it's cannot publish a message and got connection failed error. $SYS/broker/clients/active this command used to I checked it. I attach my config files given below.

My server specification:

Server: ubuntu 18.04 LTS Mosquitto version:1.6.12 Ram:4GB

My configurations:

Our system wide open connections is configured on /etc/sysctl.conf:

fs.file-max =200000

In /etc/security/limits.conf:

* hard nofile 200000
* soft nofile 200000

root hard nofile 200000
 root soft nofile 200000

Mosquitto is installed under the user 'Ubuntu'.

We also added below line of code on /etc/pam.d/common-session

session required pam_limits.so

Running ulimit -a is giving the below result:

core file size (blocks, -c) 0
data seg size (kbytes, -d) unlimited
scheduling priority (-e) 0
file size (blocks, -f) unlimited
pending signals (-i) 15623
max locked memory (kbytes, -l) 16384
max memory size (kbytes, -m) unlimited
open files (-n) 200000
pipe size (512 bytes, -p) 8
POSIX message queues (bytes, -q) 819200
real-time priority (-r) 0
stack size (kbytes, -s) 8192
cpu time (seconds, -t) unlimited
max user processes (-u) 200000
virtual memory (kbytes, -v) unlimited
file locks (-x) unlimited

Below is the configuration in /etc/mosquitto/mosquitto.conf:

persistence true
persistence_location /var/lib/mosquitto/

log_dest file /var/log/mosquitto/mosquitto.log

include_dir /etc/mosquitto/conf.d

max_connections -1

log_type error
log_type warning
log_type notice

connection_messages true```

How to increase my mosquitto broker connection limits?
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