Why are ports not opening on Ubuntu Server 16 at Digital Ocean?

Question

linux

On the Ubuntu Server 16 server in Digital Ocean, some ports need to be opened (for example, 8099)
On this server, ISP Manager Lite is also installed (which also has a firewall, but there are no added rules)
On the local, I check with the command nmap --open host_ip
Not shown: 994 filtered ports, 2 closed ports
PORT STATE SERVICE
80/tcp open http
443/tcp open https
1500/tcp open vlsi-lm
2022/tcp open down
I already installed ufw on the server, added rules and activated, here is the output of sudo ufw status
Status: active
To Action From
-- ------ ----
8099 ALLOW Anywhere
80 ALLOW Anywhere
443 ALLOW Anywhere
2022 ALLOW Anywhere
1500 ALLOW Anywhere
8099 (v6) ALLOW Anywhere (v6)
80 (v6) ALLOW Anywhere (v6)
443 (v6) ALLOW Anywhere (v6)
2022 (v6) ALLOW Anywhere (v6) )
1500 (v6) ALLOW Anywhere (v6)
On the server, the required port is open, but supposedly from the outside it does not work.
Could there be a problem with the ISP manager, which overrides its default rules?
How to understand what is the problem?

Answer 1

The problem is that the ISP itself blocks these ports outside the droplet to fight spam.